Tag Archives: QHY183M

A step by step guide to Collimation

If like me you own some sort of reflector telescope, whether this be a Newtonian, Dobsonian, Ritchey Chretien or as I have a Hyperboloid Astrograph then you’ll know that there is a very strong importance on collimation, the faster the optics the more critical collimation becomes, especially for imaging. After recently removing the rear mirror assembly for cleaning, as well as changing from the QHY183M to the QHY268C-PH amongst onther stuff in the imaging train, I wanted to share my experience and knowledge around collimation. Let’s start off with the details on what I use

Part 1 – Aligning the Secondary Mirror with the Focuser

Now on my SharpStar 15028HNT, they recommend you unscrew and remove the corrector from the focuser, however I have found no dofference in collimation with or without the corrector in place and because it is part of the optical train I’d rather include it in the collimation, so the first step for me since my primary mirror was currently removed was to check the secondary alignment with the focuser, as well as the rotation of the secondary in relation to the focuser, in order to do this, I use the Teleskop-Service Concenter eyepiece, the eyepiece itself has a set of rings engraved into the plastic apperture like so

Teleskop-Express Concenter Eyepiece markings on lower end of barrel

I ensure that my focuser is at the most inward position and since my SharpStar has an M48 thread on the focuser, I used a 2″ extension tube that has an M48 thread on it, and placed the concenter eyepiece in there:

M48 threaded 2″ Extension tube with Teleskop-Express Concenter Eyepiece

This serves well to get the rotation and alignment of the secondary with the focuser by ensuring that the mirror appears as a perfect circle between the rings, now you can adjust your focuser position in order to get the edge of the mirror to appear on the lines, this is what the view looks like through the concenter eyepiece:

Here you can see the secondary mirror appears circular and in line with the concenter eyepiece markings showing a successful alignment with the focuser

The blue at the top right of the image is a piece of card I stuck behind the secondary in order to show the edge of the mirror better.

As you can see my secondary mirror is pretty much perfectly aligned with the focuser and square with the focuser also, if your mirror shows up as more eliptical, this means the mirror needs to be rotated, if the mirror does not fit in within the circle itself, for example if it is over to the left or right, you will need to move the mirror forward or backwards by means of loosening or tightening the central screw that holds the secondary.

You can see from the following image, I have a central screw which is used for moving the mirror up or down the tube away from or closer to the primary, as well as rotation of the mirror, but then there is also the three collimation screws that are used to adjust the mirror direction itself which we will talk about in the next section

Here you can see the central adjustment screw for adjusting the mirror rotation and centering the mirror with the focuser, the three outer scres are used for adjusting the tilt of the mirror to align with the primary

Part 2 – Aligning the Secondary Mirror with Primary Mirror

Now that we have our secondary mirror lined up and square with the focuser, the next step is to align the secondary with the primary, now for this I will use my FarPoint Astro Laser collimator, which itself has recently been collimated by FarPoint Astro, now you can re-use use the 2″ extension tube and place the laser into the tube, but for the SharpStar I will use the M48 to 1.25″ lockable adapter like so:

FarPoint Astro laser collmator in the SharpStar M48 to 1.25″ Adapter

Now the point of this part is to ensure that the laser hits the centre spot of the primary mirror, if it does not, then this is where you would adjust one or more of the three screws on the secondary, as you undo one, you should tighten the other two, as you can see from this image, I need not make any adjustments as the laser hits the centre of the primary perfectly:

Here you can see that the laser hits the primary mirror centre spot

Part 3 – Aligning the Primary Mirror

Now since I do not have to make any further adjustments to the secondary mirror, it is time to focus on the primary mirror, the trick here is to get the laser beam to return to the point of origin, here’s an example of the primary not being correctly aligned:

You can see two dots here, one is the laser aperture, the other is the reflection of the laser from the primary mirror, this reflection needs to meet the aperture

You can clearly see the red dot to the top left of the laser apperture, this means that the primary needs some adjustment by means of the three collimation screws which are situated on the rear of the primary mirror assembly:

Here you can see the primary mirror collimation screws, the larger push/pull the mirror, the smaller are locking screws to secure the mirror in place after successfully collimating.

Most telescopes have a push – pull method here, turning anti-clockwise will push the mirror further up the tube, whereas turning clockwise will pull the mirror towards the bottom of the tube, it is very important not to keep turning anti-clockwise because this could result in the screws becoming disconnected from the primary mirror. After an adjustment on a couple of the collimation screws, my primary is now aligned properly as the laser beam returns into the laser apperture:

Here you can see that there is no additional dot, the dot is centered right on the laser aperture indicating primary alignment is complete

Once the laser collimation has been completed, it is easy to verify this with the FarPoint Auto-Collimator, the eyepiece has a mirror inside which allows you to see where the centre spot of the mirror is and will form a slightly pale dot in the middle, if the dot appears in the middle then you have your collimation pretty much spot on after following the above, maybe a very slight adjustment on the primary collmation screws is all that is required, you can see here what the view looks like:

It is also normal on faster telescopes to see the mirror appearing offset as opposed to central to the OTA itself. Once completed, I would typically then perform a star field test and I prefer to use the Multi Star Collimation in CCD Inspector for this, you can of course use the de-focused star method.

I hope you found this useful, I just thought I would share my process in performing collmation to help others who may be on that journey also.

QHY268C APS-C Colour Camera Review – Part 1

As many of you know, I have been using QHY cameras for a while, but with my plan to move to a RASA telescope next year and wanting to image with a bigger sensor than the QHY183M I decided to go for a bigger sensor but moving away from Mono, the latest addition to the QHY familly is the QHY268C Photographic Version. I had been talking to the QHY team for a long time about this particular camera, and finally I have one.

The QHY268C is a once shot colour camera based on the APS-C Sized back illimunated Sony IMX571 sensor, the camera has a true 16-Bit Analog to Digital Convertor (ADC), now there are a few camera models out there using this sensor, cameras such as the ZWO ASI2600, but one thing that sets the QHY268C apart from the others is the ability to have a 75ke full well capacity which is 25ke higher than the ZWO ASI2600. In my opinion, when imaging at fast focal ratios, a higher full well is desired to protect the colour around bright stars for example.

Opening the box I was greeted with a camera that was bigger and heavier than my 183M, but then the sensor is much bigger than the 183M anyway so this would be expected, but what I did not expect is the additional items that came with the camera:

Inside the box was:

  • QHY268C Photographic Version
  • UK mains plug for 12V AC adapter
  • 12V AC adapter
  • Car 12v power cable
  • Self locking power cable
  • 1.5M USB 3.0 cable
  • Dessicant drying tube
  • Self centering adapter plate
  • M54 to M48 adapter plate
  • M54 to 2″ nose adapter
  • A range of spacers to give you from 0.5mm to 13.5mm spacing
  • Associated screws for spacing adapters

QHY cameras have come along way since I bought my QHY183M, one of the things QHY has really worked on is amp glow, my early version of the QHY183M was renowned for was amp glow, which could be removed in image calibrations, but the QHY268C produces no amp glow whatsoever, below is a dark frame of 600S taken at -13.5C and you can clearly see there is no evidence of amp glow.

Single frame 600 seconds, Gain 26, Offset 30, -13.5C – Mono (Not Debayered)

Attaching to the telescope was pretty straight forward as I had already planned the imaging train before the camera arrived, since I will be using the SharpStar 15028HNT F2.8 Paraboloid Astrograph which has an M48 thread, I decided to keep the whole imaging train at M48 except for the camera of course which has an M54 thread, so I did not actually need to use any of the adapters that came with the camera, the reason for this is because I wanted to include a filter drawer, so my image train consists of the following (from telescope to camera)

  • TSOAG9 – TS Off Axis Guider (9mm)
  • TSOAG9-M48 – TS M48 Adapter for the OAG (2.5mm)
  • TSFSLM48 – TS 2″ Filter Drawer with M48 Thread (18mm)
  • M48AbstimmA05 – TS Optics 0.5mm Aluminium spacing ring (0.5mm)
  • TSM54a-m48i – TS M48 to M54 Adapter (1.5mm)
  • QHY268C with M54 Centering Adapter (23.5mm)

As you can see with all the above I reach my desired back focus of 55mm perfectly, if I was not going to be using a filter drawer (For my Optolong L-Pro and L-eXtreme filters), I would probably have stuck with the spacers that came with the camera. Below is a picture of the camera successfully connected to the telescope.

As far as settings go, after speaking with QHY on this at great length, I will be imaging in Mode 0 (Photographic mode) to avail of the massive 75ke full well, offset I will leave at 30, but Gain I will use two different settings, I will use Gain 0 for most bright objects with the L-Pro filter, but for the L-eXtreme, I’ll probably set a gain level of 26, luckily with SGPro I can set the gain level per object. From a cooling perspective I always image at -20C, one thing I have noticed is that this camera cools to exactly -35C below ambient, I tested this when the ambient temperature was 20.10 degrees, and the camera cooled down to -14.9C, it was always 25C lower until the ambient dropped below 15C and the camera remained at my setting of -20C.

The build quality of the camera is as expected having owned a QHY183M, one thing I did notice is that the fan in the QHY268C is much quieter than the 183M. Technical Details of the camera:

CameraQHY268CQHY183M
Image SensorSony IMX571Sony IMX183
Sensor SizeAPS-C1″
IlluminationBack IlluminatedBack Illuminated
Pixel Size3.76um2.4um
Effective Image26mpx20mpx
Full well capacity51ke
(75ke in extended mode)
15.5ke
ADC16-Bit12-Bit
Image Buffer Memory1GB/2GB128MB
Max Cooling Delta-35C-40C
Weight1006g650g

I can’t wait to get imaging with this camera, I have a very aggresive target list for this year in both RGB and Narrowband with the Optolong L-eXtreme filter, I will write part two of the review once I have some actual imaging data. Time to build my dark library.

SharpStar 15028HNT

After months of trying to get my trusty Sky-Watcher Quattro F4 to work with the ASA 0.73x reducer I decided to go all in on an F2.8 astrograph. After doing some research I stumbled across the SharpStar 15028HNT F2.8 Hyperboloid Newtonian Reflector from my local supplier 365Astronomy.

After toying with the idea and speaking to my good friend Nick from Altair Astro and with the idea of going back to a refractor, I decided that I could not go back to slower than F4 and I wanted something that in essence would work with a bigger sensor than my QHY183M, and the Sharpstar looked like it could work for me, so I placed my order with Zoltan from 365Astronomy and collected it the following day.

Unboxing the scope, I was like a young child at christmas, the scope came with a very sturdy protective hard case and removing the scope out of the case you could immediately feel that a lot of time and effort had gone into producing the 15028HNT.

Aperture: 150mm
Focal Length: 420mm
Focal Ratio: F2.8
Weight: 6kg
Tube Material: Carbon Fiber

With the scope unboxed I started to fit my equipment onto the scope. In order to fit my Sesto Senso I had to rotate the focuser 90 degrees clockwise due to the telescope mounting rings, this is when I noticed an isue that one of the grub screws on the focuser would not tighten and I needed to stop the backlash, fortunately there’s another grub screw on the other side that tightened and stopped the backlash.

Before I attached my imaging equipment, I had to ensure that the telescope was collimated, so I stumbled across the collimation guide which after speaking with my good friend Terry Hancock over at Grand Mesa Observatory who was also evaluating the same scope, we both agreed that the colimation guide wasn’t very well written as it mentioned nothing about collimating the primary. One thing that it mentioned is to remove the corrector, Sharpstar include a tool for you to remove the mounting plate and corrector, but here is a word of advice……..remove this when the telescope is cold, take that advice from someone who tried to remove it whilst it was warm!

I performed a laser collimation with my Concenter Eyepiece to check the secondary, and then a laser to check the primary, now the collimation guide says to remove the corrector, I have done validation with both the corrector removed and the corrector in place, and it made no difference whatsoever, so my opinion is to leave the corrector in place.

With the scope closely collimated, I mounted my StarlightXpress Filterwheel and Camera which with the 15028HNT is an M48 thread for the gear to screw onto.

I will post some images as soon as I have completed some, the weather has been pretty poor (probably because I bought a new scope), but the frames I have got so far are very sharp, pinpoint and I can honestly say I have never seen images come directly off the camera so sharp.

My field of view with the QHY183M is around 1.21 Arcsec/Pixel which gives me a FOV or around 1.81°x1.2° and I love the difraction spikes being at 45 degrees compared to the 90 degrees on the skywatcher and I already have a pretty full target list for this scope ready to go this season.

Apart from the couple of product issues I have experienced (Grub screw on focuser and tube clamp thumbscrew being threaded) I am extremely happy with the scope, it is performing really well and here are a couple of work in progress images that I have started

Dark Shark Nebula Moscaic Panel 1 – 51x300S in Red, 25x300S in Green and Blue
Elephant’s Trunk – 51x300S in 6nm Ha
M45 – Mosaic Panel 1 – 12x150S in R, G and B

After a few weeks, the telescope has held collimation very well, I have not had to perform any re-collimation, I will re-evaluate this in the much colder months of winter.

I am so happy with the scope that I am actually considering a second one for an OSC Camera with a bigger sensor.

M101 / NGC 5457 – Pinwheel Galaxy in RGB

M101 / NGC5457 or most commonly known as the Pinwheel Galaxy is a face on spiral galaxy in Ursa Major and has a distance of around 21 million light years from Earth.

The QHY183M picks up quite a lot of the Ha detail in this galaxy without me having to image separate Ha Filter data

Image Details:
101x150S in R
101x150S in G
101x150S in B

Total Capture time: 12.6 Hours

Acquisition Dates: Feb. 27, 2019, March 29, 2019, March 30, 2019, April 1, 2019, April 11, 2019, April 12, 2019, April 14, 2019

All frames had 101 Darks and Flats applied

Equipment Details:
Imaging Camera: Qhyccd 183M Mono ColdMOS Camera at -20C
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Sky-Watcher Finder Scope
Mount: Sky-Watcher EQ8 Pro
Focuser: Primalucelab ROBO Focuser
FIlterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium RGB
Power and USB Control: Pegasus Astro USB Ultimate Hub Pro
Acquisition Software: Main-Sequence Software Inc. Sequence Generator Pro
Processing Software: PixInsight 1.8.6

NGC4565 – Needle Galaxy in RGB

The Needle Galaxy is located int he constellation of Coma Berencies and is an edge on spiral galaxy at a distance of 30-50 million light years from earth

Image Details:
101x150S in R
101x150S in G
101x150S in B

Total Capture time: 12.6 Hours

Acquisition Dates: Jan. 28, 2019, Feb. 3, 2019, Feb. 25, 2019, Feb. 26, 2019, Feb. 27, 2019, March 26, 2019, March 29, 2019, March 30, 2019, April 1, 2019

Equipment Details:
Imaging Camera: Qhyccd 183M Mono ColdMOS Camera at -20C
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Sky-Watcher Finder Scope
Mount: Sky-Watcher EQ8 Pro
Focuser: Primalucelab ROBO Focuser
FIlterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium RGB
Power and USB Control: Pegasus Astro USB Ultimate Hub Pro
Acquisition Software: Main-Sequence Software Inc. Sequence Generator Pro
Processing Software: PixInsight 1.8.6

NGC 2264 – Cone Nebula and Christmas Tree Cluster in HaRGB

Located in the constellation of Moneceros, this image shows both the Cone Nebula and the Christmas Tree Cluster, located around 2600 light years from earth the Cone Nebula being an emmision Nebula

Image Details:

101x150S in R
101x150S in G
101x150S in B
101x300S in Ha

Total capture time: 21 Hours

Acquisition Dates: Jan. 9, 2019, Jan. 31, 2019, Feb. 3, 2019, Feb. 14, 2019, Feb. 15, 2019, Feb. 23, 2019, Feb. 24, 2019, Feb. 25, 2019, Feb. 26, 2019, Feb. 27, 2019, Feb. 28, 2019, March 24, 2019, March 25, 2019, March 26, 2019, March 28, 2019, March 29, 2019

The NBRGB Script in PixInsight was used to blend the Ha into the RGB Image

101 Darks, Flats and Flat Darks were used in the frame calibration

Equipment Details:
Imaging Camera: Qhyccd 183M Mono ColdMOS Camera at -20C
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Sky-Watcher Finder Scope
Mount: Sky-Watcher EQ8 Pro
Focuser: Primalucelab ROBO Focuser
Filterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium RGB and Ha
Power and USB Control: Pegasus Astro USB Ultimate Hub Pro
Acquisition Software: Main-Sequence Software Inc. Sequence Generator Pro
Processing Software: PixInsight 1.8.6

M78 / NGC 2068 in RGB

This is the first time I have ever imaged this object, I will re-visit next year when I will image at F2.8 with a wider field of view using a keller reducer.

Since this object is in the southern area of sky, I am limited by trees and the house on the data I can capture in a single night

Image Details:
101x150S – Red
101x150S – Green
101x150S – Blue

101 Darks, Flats and Dark Flats

Image Acquisition Dates: Jan. 1, 2019, Jan. 2, 2019, Jan. 8, 2019, Jan. 9, 2019, Jan. 27, 2019, Jan. 28, 2019, Jan. 30, 2019, Feb. 10, 2019, Feb. 20, 2019, Feb. 23, 2019, Feb. 24, 2019, Feb. 25, 2019

Equipment Used:
Imaging Camera: Qhyccd 183M Mono ColdMOS Camera at -20C
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Sky-Watcher Finder Scope
Mount: Sky-Watcher EQ8 Pro
Focuser: Primalucelab ROBO Focuser
FIlterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium RGB and Ha
Power and USB Control: Pegasus Astro USB Ultimate Hub Pro
Acquisition Software: Main-Sequence Software Inc. Sequence Generator Pro
Processing Software: PixInsight 1.8.6

IC36 Y Cas Nebula in SHO

Located in the constellation of Cassiopeia this rather feint nebula is illuminated by a very bright Magnitude 2.15 star Navi

Image Details:
101x300S in SII – Red Channel
101x300S in Ha – Green Channel
101x300S in OIII – Blue Channel

Total integration time: 25.2 Hours

101 Darks, Flats and Dark Flats applied

Acquisition Dates: Oct. 27, 2018, Dec. 13, 2018, Dec. 27, 2018, Jan. 1, 2019, Jan. 2, 2019, Jan. 4, 2019, Jan. 8, 2019, Jan. 9, 2019, Jan. 11, 2019, Jan. 18, 2019, Jan. 20, 2019, Jan. 23, 2019, Jan. 27, 2019, Jan. 28, 2019, Jan. 30, 2019

Equipment Details:
Imaging Camera: Qhyccd 183M Mono ColdMOS Camera at -20C
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Sky-Watcher Finder Scope
Mount: Sky-Watcher EQ8 Pro
Focuser: Primalucelab ROBO Focuser
FIlterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium Ha, SII and OIII
Power and USB Control: Pegasus Astro USB Ultimate Hub Pro
Acquisition Software: Main-Sequence Software Inc. Sequence Generator Pro
Processing Software: PixInsight 1.8.6

IC5146 / Cocoon Nebula in HaRGB

This is my first time ever imaging this target, and like the Crescent Nebula and Pelican Nebula I am limited to a 2.5 hour window per night to acquire data due to trees / house getting in the way, luckily I managed to get a lot of Ha data on this subject to blend this into the RGB image which smoothed out the lack of data for RGB somewhat, I would have liked to have got more RGB Data and I may re-image this with longer exposures on RGB next time also

Cocoon Nebula in HaRGB
Cocoon Nebula in HaRGB with PIxInsight 2x Drizzle

Image Details:
56x150S in R
56x150S in G
66x150S in B
101x300S in Ha

Acquisition Dates: Sept. 25, 2018, Sept. 27, 2018, Sept. 29, 2018, Oct. 20, 2018, Oct. 22, 2018, Oct. 26, 2018, Oct. 28, 2018, Oct. 29, 2018, Nov. 14, 2018, Nov. 17, 2018, Nov. 18, 2018, Nov. 30, 2018, Dec. 7, 2018, Dec. 9, 2018, Dec. 12, 2018, Dec. 13, 2018, Dec. 27, 2018, Jan. 4, 2019

All frames had 101 Darks and Flats applied, the Ha layer was blended using the new NBRGB Script in PixInsight 1.8.6, the more zoomed in picture is of the same data but with a 2x drizzle applied then cropped

Equipment Details:
Imaging Camera: Qhyccd 183M Mono ColdMOS Camera at -20C
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Sky-Watcher Finder Scope
Mount: Sky-Watcher EQ8 Pro
Focuser: Primalucelab ROBO Focuser
FIlterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium RGB and Ha
Power and USB Control: Pegasus Astro USB Ultimate Hub Pro
Acquisition Software: Main-Sequence Software Inc. Sequence Generator Pro
Processing Software: PixInsight 1.8.6

Flickr Link: https://www.flickr.com/…/465843…/in/album-72157688487449350/

AstroBin Link: https://www.astrobin.com/384658/

NGC6888 – Crescent Nebula in SHO Narrowband

This object is a little tricker for me since I only have a 3-3.5 hour window per evening due to trees and the house blocking my view, this is also the first image that I used the drizzle function within PixInsight to be able to provide a detailed up close version of the image, I was very happy to have captured the brown “Globules” within the nebula to

Crescent Nebula in SHO Narrowband
Same object but with a 2x drizzle function in PixInsight applied

Image Details:
Red Channel – SII Data – 89x300S
Green Channel – Ha Data – 64x300S
Blue Channel – OIII Data – 109x300S

101 Darks, Flats and BIAS Frames used 

Equipment Used:-
Imaging Camera: QHY183M Mono ColdMOS Camera at -20C
Imaging Scope: Skywatcher Quattro 8″ F4 Newtonian
Guide Scope: Skywatcher Finder Scope
Guide Camera: QHY5L-II
Mount: Skywatcher EQ8 Pro GEM Mount
Focuser: PrimaluceLabs ROBO Focuser
Filterwheel: StarlightXpress 7x36mm EFW
Filters: Baader 7nm Ha, SII and OIII
Acquision Software: Main Sequence Software Sequence Generator Pro
Processing Software: Pixinsight 1.8.5