Is what I’m shooting any good?

[Matt S]

A new post as this feels like a better place than my previous thread. 

I think I’ve got a reasonable plate solving setup now (albeit, it can still fail if it gets to a sot with few visible stars). 
 

I spent a bit of time trying to image M18, but had issues trying to process these in Siril (not enough stars, and when I relaxed this, it ended up rejecting 99 of the 100. I ended up stacking in Affinity, but I’m not seeing to much right now.

As this was a first run / seeing if things were working attempt I didn’t shoot any darks/flats etc, only lights. A mix of 10, 20, 30 and 60s subs.

I’ve attached a single Fits from one of what I thought looked a better shot… I guess my question is from  anyone with more experience than me is - does this look any good (for a single shot)? 

equipment:
Skymax 127

Asi678mc

EQ3-2 / Ekos (unguided)

 

 

m81.tiff M_81_Light_001.fits

[Clarkey]

I think that with the Skymax at F12 and the mount you are using, in particular without guiding, you are going to really struggle. The combination you have is OK for lunar and planetary imaging with a motor drive- but not really good for DSO's. It would appear that you do have the core of M81 in the image, but it is difficult to see much more. It is also very noisy.

Personally, given the limitations of your mount, I would suggest trying some widefield shots. Even at much shorter FL's you may still struggle. Unfortunately, in AP the mount is the critical part, and the EQ3-2 is probably not up to the task.

[ONIKKINEN]

f/12 with the tiny 2 micron pixels of the 678MC is going to be a really bad time with DSO imaging. Not saying its impossible, but we are getting there especially since you are not guiding.

If you wanted to try and make this work you would need to guide and expose for probably at least 5 minutes (as long as possible really) for the images to be something other than mostly noise and for stars to start to be visible beyond the noise.

Really the sanest approach to starting DSO imaging with your mount/camera is with another scope. Probably some short focal length refractor which will be more forgiving with your short exposures and lack of guiding. The camera is still not optimal and maybe you would have better luck with something else, i think you may have pretty much one of the worst combinations of kit for DSO imaging with all this, sorry!

[Elp]

Binning the camera will help. But I've experienced similar when imaging at F6.3 Vs F5.9 and F2, the signal is just that much dimmer when spread out on tiny pixels at the slower ratio, larger pixels will increase the probability of photons hitting them hence will improve signal but needs to be paired with optics which allow the light to stimulate the sensor. With a decent optical system, stars will be extremely easy to capture in order for software to register each image.

Edited April 10 by Elp

[alacant]

1 hour ago, Matt S said:

Skymax 127

Hi

I think you may have missed focus or the seeing was poor. Not sure how many clear nights you have where you are but at 1500mm you're going to be limited to the few which have excellent seeing.  A few ideas:

How about attaching your 678 to a camera lens instead? There are some good examples to be had for under €100 e.g. fixed focal length Takumar and Zeiss between 55mm and 200mm. Your mount will be able to cope admirably with that combination. Keep your 127 to look through and take -superb- photos of the surface of the moon.

Another idea is to fit a reducer.

Another, to upgrade the mount and guide but even then...

Cheers and HTH

Edited April 10 by alacant

[ollypenrice]

20 minutes ago, alacant said:

Hi

I think you may have missed focus or the seeing was poor. Not sure how many clear nights you have where you are but at 1500mm you're going to be limited to the few which have excellent seeing.  A few ideas:

How about attaching your 678 to a camera lens instead? There are some good examples to be had for under €100 e.g. fixed focal length Takumar and Zeiss between 55mm and 200mm. Your mount will be able to cope admirably with that combination. Keep your 127 to look through and take -superb- photos of the surface of the moon.

Another idea is to fit a reducer.

Another, to upgrade the mount and guide but even then...

Cheers and HTH

Since the mount won't allow the system to resolve at anywhere near its sampling rate, it may be that losses to the seeing fall within losses to the tracking error and so won't make much difference. Hard to know.

I entirely agree with you on the use of a camera lens. Surely that's the way forward with a small chip, tiny pixels and no accurate guiding.

When I started, I remember being very skeptical when people said, 'That system won't work.'  I learned fairly soon that they were right, though.

Olly

[Matt S]

On 10/04/2023 at 15:41, ONIKKINEN said:

The camera is still not optimal and maybe you would have better luck with something else, i think you may have pretty much one of the worst combinations of kit for DSO imaging with all this, sorry!

On 10/04/2023 at 16:03, alacant said:

How about attaching your 678 to a camera lens instead? There are some good examples to be had for under €100 e.g. fixed focal length Takumar and Zeiss between 55mm and 200mm.

On 10/04/2023 at 16:30, ollypenrice said:

I entirely agree with you on the use of a camera lens. Surely that's the way forward with a small chip, tiny pixels and no accurate guiding.

Thanks everyone - bit of a learning curve to see what I can/can’t manage with my setup really. I’d never intended it to be a DSO setup, but it’s got me interested now… so I figured I’d dabble whilst I’ve lost the planets from my current location. 
 

I’d been going with the idea of getting a Svbony 503 after seeing someone use that on a Eq3 with good (to me) results.. I would of course like a new mount but that will be further down the road. 
I’ll check out using a camera lens - I may have something usable.

I tried again on M81 with some tweaks/longer exposures - but as you guys said, that’s when the tracking fell apart and things started trailing. 
 

I did however have a little more success with M3, although I found taking exposures over 20s more punishing than 30+ seconds pointing at M81 - I’m not quite sure why, possible the mount angle / wind, or possibly the difference in the target.

I still think my focus is off, I’ll need to figure out what I’m doing there - and I have a LOT to read/learn on what I should be doing to capture / process shots - but anyway, here’s my 2nd attempt at shooting anything other than a planet.

Nothing as lovely as I’ve seen you all produce, but it’s a little progress for me, so I’m pleased (it’s also nice having my scope solve and point then switching to visual - much more accurate than my go-to).