Tag Archives: asi6200mm pro

Eternal Quest: The Elephant’s Trunk Nebula Unveiled

In the boundless theatre of the night sky, where celestial tales unfold across the eons, lies an ethereal masterpiece that has captivated the gaze of astronomers and dreamers alike. This image, a delicate two-panel mosaic, is a profound revelation of the Elephant’s Trunk Nebula, known formally by its catalog designations IC 1396A, nestled within the larger expanse of the IC 1396 complex in the constellation of Cepheus.

Crafted with meticulous dedication over the span of five months, this portrait of the cosmos was brought to life using a full-frame monochrome CMOS camera, a testament to the intersection of art and technology. The camera, acting as a modern-day alchemist, transformed the invisible into the visible, capturing the nebula’s intricate details and sweeping gas clouds that resemble an elephant’s trunk, reaching out into the void.

However, this image is more than a snapshot; it is a chapter in an ongoing saga dictated by the unpredictable whims of the UK’s weather. The journey to encapsulate the nebula’s full glory has been a dance with the elements, with many nights spent under the cloak of clouds rather than stars. Despite these challenges, the initial results have unveiled a stunning glimpse into the cosmos, showcasing the nebula’s haunting beauty and the vibrant activity within its star-forming regions.

Yet, the story does not end here. The image is a promise of what is yet to come, as there are plans to revisit the Elephant’s Trunk Nebula later this year. The aim is to deepen the exploration, to add more data to this cosmic tapestry, and to further refine the clarity and depth of this celestial phenomenon.

This endeavor, a blend of patience, passion, and precision, highlights not just the technical prowess required for astrophotography but also the enduring human desire to connect with the universe. Through this image, we are reminded of our place in the cosmos, a mere speck within the vastness, yet capable of capturing and celebrating its majesty.

The Elephant’s Trunk Nebula stands as a beacon in the dark, a symbol of the mysteries that await our discovery. With each photograph, we peel back another layer of the universe, bringing us closer to understanding the grand design of which we are a part. This image is an invitation to gaze upwards, to wonder, and to dream of the infinite possibilities that lie beyond our world.

Here is the Astrobin link for the full resolution image: https://www.astrobin.com/full/qxmduq/0/

Frames:
Chroma H-alpha 3nm Bandpass 50 mm: 81×300″(6h 45′) (gain: 100.00) -10°C bin 1×1
Chroma OIII 3nm Bandpass 50 mm: 91×300″(7h 35′) (gain: 100.00) -10°C bin 1×1
Chroma SII 3nm Bandpass 50 mm: 125×300″(10h 25′) (gain: 100.00) -10°C bin 1×1

Integration: 24h 45m
Darks: 51
Flats: 51
Bias: 201

Equipment:
Imaging Camera: ZWO ASI Cameras ASI6200MM Pro Gain 100 -10C
Imaging Scope: Sharpstar Optics 20032PNT F3.2 Paraboloid Astrograph
Filters: Chroma 50mm 3nm Filters
Filterwheel: ZWO ASI Cameras 7x EFW
Guide Camera: ZWO ASI 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, 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!