Tag Archives: reflector

Heart and Soul 3 Panel Mosaic

In the boundless theatre of the night sky, a spectacle of cosmic proportions gently unfolds. Here, through the unblinking eye of my camera, we witness the Heart and Soul Nebulae, celestial bodies of unimaginable scale and beauty. Captured in the vivid hues of the Hubble Palette, this image is the culmination of over 68 hours of patient vigil over the course of six months, a testament to the relentless march of time and space.

The Heart Nebula, known as IC 1805, and its companion, the Soul Nebula, IC 1848, are more than mere clusters of gas and dust. They are incubators of stars, cosmic nurseries where new celestial lives begin. Nestled within is the charmingly named Fish Head Nebula, a smaller star-forming region within this grand cosmic landscape.

Each pixel of this mosaic is a story, a tiny fragment of the universe’s narrative, captured through the artful blend of sulfur, hydrogen, and oxygen emissions. As we gaze upon this image, we are not merely observers but voyagers, embarking on an odyssey across the galaxy. It invites us to ponder our place in this magnificent universe, a reminder of both our insignificance and our profound connection to the cosmos.

In the grand scheme of things, this image is but a fleeting glimpse into the eternal dance of the cosmos. It is a humble offering to the beauty and complexity of the universe, a universe that continues to captivate and inspire us with its endless mysteries.

Catalog Names:
IC 1805 (Heart Nebula)
IC 1848 (Soul Nebula)
Fish Head Nebula (Part of the Heart Nebula)

Acquisition Dates:
16 May 2023, 17 May 2023, 20 May 2023, 21 May 2023, 25 May 2023, 26 May 2023, 27 May 2023, 28 May 2023, 15 Jun 2023, 16 Jun 2023, 24 Jun 2023, 25 Jun 2023, 26 Jun 2023, 13 Jul 2023, 16 Jul 2023, 17 Jul 2023, 19 Jul 2023, 20 Jul 2023, 25 Jul 2023, 26 Jul 2023, 6 Aug 2023, 7 Aug 2023, 9 Aug 2023, 10 Aug 2023, 17 Aug 2023, 20 Aug 2023, 22 Aug 2023, 5 Sep 2023, 9 Sep 2023, 15 Sep 2023, 23 Sep 2023, 29 Sep 2023, 8 Oct 2023, 9 Oct 2023, 14 Oct 2023, 15 Oct 2023, 6 Nov 2023, 7 Nov 2023, 10 Nov 2023, 11 Nov 2023, 14 Nov 2023, 15 Nov 2023, 19 Nov 2023, 20 Nov 2023, 22 Nov 2023, 24 Nov 2023, 25 Nov 2023

Frames:

Chroma H-alpha 3nm Bandpass 50 mm: 213×300″(17h 45′) (gain: 100.00) -10°C bin 1×1
Chroma OIII 3nm Bandpass 50 mm: 303×300″(25h 15′) (gain: 100.00) -10°C bin 1×1
Chroma SII 3nm Bandpass 50 mm: 303×300″(25h 15′) (gain: 100.00) -10°C bin 1×1

To see the image in all its glory, use the link

Equipment:
Imaging Camera: ZWO Astronomy Cameras ASI6200MM Pro Gain 100 -10C
Imaging Scope: Sharpstar Optics 20032PNT F3.2 Paraboloid Astrograph
Filters: Chroma 50mm 3nm Filters
Filterwheel: ZWO Astronomy Cameras 7x EFW
Guide Camera: ZWO Astronomy Cameras ASI290MM
Mount: Sky-Watcher EQ8 Pro German Equatorial Mount
Auto Focuser: Primalucelab Sesto Senso2
Environmental conditions: Primalucelab ECCO2
Observatory Control: Primalucelab Eagle Eagle 4 Pro
Roof Control: Talon RoR
Image Acquisition: Main Sequence Software Sequence Generator Pro
Image Calibration and Stacking: Astro Pixel Processor
Image Processing: PixInsight, EZ Processing Suite, Russ Croman’s BlurXterminator and StarExterminator

Sharpstar 20032PNT F3.2 Paraboloid Astrograph Review

Having owned the Sharpstar 15028HNT, I decided I wanted a larger light bucket without really sacrificing on speed, so I opted for the big brother of the 15028HNT which is the SharpStar 20032PNT.

I picked up my 20032PNT from Zoltan at 365Astronomy, and could not wait to get it home and unbox it, so after removing it from not just one carboard box, but two, I was presented with a very large flight case, which evidently is a larger version than the one that came with the 15028HNT.

Once I had the scope unpacked and inspected everything, the first thing I noticed was the focuser, the 20032PNT has a large focuser, which is big enough to accomodate the reducer/corrector that has an M68 connector thread as well as an M54 and an M48 connector thread.

The scope is well built, as I would expect from the build quality of the 15028HNT, the red annodised alluminium tube rings just give that final touch of finese. The 3 inch focuser is very smooth, and will no doubt be able to handle quite a load of equipment.

The first thing I planned to do was ensure that the primary mirror was secure and did not rock back and forward as well as replace the stock fan. I have fed back to SharpStar that they should mount the fan externally and also mount it with shock absorbing rubber mounters, and have the airflow into the tube from the back, rather than drawing air down the tube from the secondary. Here are my images of the fan replacement:

Primary Mirror assembly removed from OTA
Fan assembly with mirror removed
Stock Fan

Stock fan removed and added in a PWM fan connector should the fan ever need to be replaced, it can be replaced without removing the mirror assembly
Anti vibration fan mounting points
External fan connected to PWM connector
How the fan looks from the outside, the image is missing the fan filter which I added afterwards

Once everything was back together, I mounted my Eagle4Pro onto the top bar, as well as added an extra long losmandy plate because I wanted the OTA as far forward as I could get it in order to have the camera in the right location without it hitting the mount at all.

And here is the scope on the mighty EQ8 Pro mount

My first set of image testing did not go so well. My previous 15028HNT did not protrude above the walls of the observatory, so despite the fact that the secondary mirrors on both scopes are right up at the top of the tube, the 20032PNT was picking up stray light from my neighbour, so I had to adopt a dew shield that would extend the OTA by around 5 inches:

Scope with dew shield attached

Flats
I first started to have issues with my flats that was taken with a flat panel, the flat frames would “Overcorrect” the images, but one thing I noticed that there was a lot of vignetting happening. Sky flats seemed to work better, but I was not happy with the vignetting. Now since I am using a full frame sensor on the ASI6200MM Pro, and the scope supports full frame, I was a little intrigued as to why I was getting so much vignetting, you can see from the master flat below that there was indeed a significant amount of vignetting.

Red Master Flat in PixInsight

I did some calculations and found what my problem was. Since my camera is full frame, it has a diameter of 44mm. The M54 connector on the telescope is 55mm away from the sensor, so a simple equation tells me that my light cone is larger than the M54 connector:

Sensor diameter + (distance from sensor / focal ratio)
44 + (55/3.2) =61.1875mm

The internal diameter of the M54 connector is around 51mm, so the light cone was being restricted by around 10mm. So I had a custom M68 to M54 adapter made which is 28.5mm in length, the reason for this is because the backfocus from the M68 connector is 61mm, so if we apply our formula:

44 + (61/3.2) = 63.06mm, this is way below the internal diameter of the M68 connector male thread, so vignetting should be minimised. Now because I do have some M54 in my image train, I know I would not completely elliminate vignetting and this is why, using the above formula, we can work out the light cone at varying part of the imaging train:

12.5mm (EFW mating to camera) = 47.9mm
18mm (50.4mm Filters distance from sensor) = 49.62mm
32.5mm (Light entrance to EFW distance from sensor) = 54.15mm

As you can see, I should expect some vignetting to occur because the light cone at the EFW M54 connector (with around 51mm internal) is 54.15mm, so I would be clipping the light cone slightly, but the result is as follows, again red filter, you can see that the vignetting is significantly reduced:

Collimation was done using the exact same process I used on the 15028HNT, you can read the guide here.

Conclusion:
SharpStar have again produced an outstanding quality astrograph, with a massive focuser to take on the largest of imaging trains, as well as finishing off the product with high quality annodised OTA rings. I am extremely happy with the performance of the telescope, below is my first image which happens to be a 2 panel mosaic:

Iris Nebula, 2 Panel Mosaic, Each Panel consists of 151x60S frames at Gain100, for L, R, G and B, for the full resolution image please use this link

Backfocus information:
M42 connector: 53mm
M54 connector: 55mm
M68 connector: 61mm

Focal Length (With Reducer/Corrector): 640mm
Focal Ratio: F3.2
Newtonian Type: Paraboloid
Focuser Size: 3″

The only complaint I have is with regards to the fan, which I have made a suggestion to SharpStar on that. Good job again SharpStar!

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.