Datalord

No, I haven't done either of those. I am pigheaded when it comes to software; I insist on getting through all the problems myself, so I can learn from them. And sometimes I just flip the table and go elsewhere... ☹️

Maybe I should give it another go. I would love to be able to just automate all that, especially the focusing and warmup parts. I just had entire nights go to the bin because of random nonsense. 

Interesting thread. 

I have to say I'm sceptical of your plans for having sequence control everything. I find it very flimsy, with a nasty habit of crashing. So much so that I don't ever use it. Yes, it means I don't get the benefit of unguided runs, but the asa is doing better than I could ever imagine with my guided setup. 

Only seen this now. Had quite a hiatus, mostly due to cloudy formations. Beautiful scope. With the g3-16200 we will have almost identical setup. 

Have you had first light yet? 

I got interested in the Abell catalog and in August decided to throw some hours after Abell 262. This cluster is relatively small, and relatively close by, with a mere 200M light years to go. Which also makes it achievable with my modest equipment. I love these clusters and will do more of them.

Captured from E-Eye using my RC and G3-16200 on an ASA DDM85.

• R: 46*180s bin2
• G: 46*180s bin2
• B: 44*180s bin2
• L: 38*300s bin1
• 10 hours of data in total, gathered mid august.

I found 53 fuzzies. How many do you see?

On 28/03/2019 at 15:46, Rick_It said:

Yes, but a C8 is not a rich-field scope, so it's not universal. For example, you can't frame the Pleiades. With a 200/1200 you get up to 2.26° FOV.

Which is exactly why the answer to the question is "No". 2.26 degrees is not at all awesome if you're shooting galaxy clusters 200MLY away.

My RASA is good for pleiades and Orion etc, but utterly useless for the Abell Catalog. My RC is doing great as a galaxy hunter, but would require a huge mosaic to get Orion. 

6 hours ago, vlaiv said:

which again is not really any harder to do than downsampling flats

it is considerably harder to do when you can't use a flat panel because of the combination of blowing out the ADU and a mechanical shutter. I only have 40 min of light suitable for flats, IF there are no clouds. Last time it took me 20 days to coordinate a full set for all filters...

18 hours ago, vlaiv said:

That is something you should always do, regardless of any binning applied (before or after) - use exact same settings for calibration files.

yes, in an ideal world. My own experience tells me the downsampled flats work great.

18 minutes ago, Ken82 said:

So should be at 0.5” per pixel but due to the pixels I think it’s now more like 1” per pixel . Or at least that’s what I understand 😀

The resolution doesn't matter.  They are used to calibrate the images and whether you are shooting at 0.1" or 15" is irrelevant. It's the resolution of the image itself, x*y, that needs to match, with the dust bunnies in the right place. 

12 hours ago, Ken82 said:

I just acquired a few flats earlier at 1.2s ADU 20000. Hope that works .

You can go higher, as long as you're not clipping in the top. I start my run at 30k-40k at 0.5s and stop when I can't get it above 10k with 5s exposures.

On 29/09/2019 at 13:12, Ken82 said:

I have read elsewhere some are having to use longer exposures for flat frames as these cameras are unreliable with short exposures.

*raises hand*

I have a 12" RC combined with a mechanical shutter. It's a pestilence to acquire flats. I can't use a panel, because it blows out the ADU, because the manual shutter only allows me to go down to 0.5s exposures. I have a grand total of 40 min at dusk to gather flats, so last round took me a month.

Btw, I take them bin 1x1 and downsample in PI for other binnings. Works perfectly.

46 minutes ago, Adam J said:

That's why it overcomes F10. If you stick a asi1600 on it do you really think you would get this result with 2min subs? 

I don't understand the fuss. I shoot at f/8 with my RC. Even at very modest 12" I have to pace my subs from blowing out with a G3-16200, so f/10 can't be that different. 

3 hours ago, pete_l said:

I don't think it works like that

I would argue it is exactly like that, but the choice of changing is a matter of deciding how often you are willing to go through these motions. 

As someone who went through the motions of cheaper gear and pain, I will advice anyone to buy dedicated equipment for each purpose. Accept limitations, learn strengths and later expand to more setups. The fewer moving parts, the better. 

On 16/09/2019 at 11:44, jinchuriki said:

Just to point out for the mount, were you referring to the CGX, or CGX-L? As it has a fairly big difference between the 55 LBS for CGX and 75 LBS for the CGX-L.

Late to the party, but as DaveS pointed out, I have been a CGX user. Not CGX-L, true, but the difference between those two is a bit of size, not actual mechanic ability. Stay FAR away from Celestron if you want "a lifelong setup".

As to what others point out, the difference between long FL DSO and short (I have a RASA as well as a 12" RC) is unbelievably big. Everything is different. Deciding one night to change from hyperstar to long FL means recalibrating balance, new polar alignment, flats have to be done all over again, camera changed, unless you use CMOS colour, image processing is different. I could go on and on. DaveS had the wisest words:

On 16/09/2019 at 11:25, DaveS said:

With DSO imaging the fine tuning to get the best results is so finicky that once you've got everything playing nicely together LEAVE IT ALONE until you start seeing problems.

As has been said elsewhere in this thread, you seem to have your heart set on this Celestron setup, but lifelong it is not. You will learn a ton of stuff, you will have some good photos and it might be just great. But you will become annoyed over time and you will upgrade. That is my prediction. I can only hope you don't get Post Traumatic Mount Disorder with that CGX.

I had a thread with a cmos and my RASA showing similar issues. I settled on atmospheric dispersion, which moves the red light different from blue. I suspect this effect is increased with aperture, so your 14 will be more susceptible. I had a whole thread on it earlier this year. 

It you do your collimation in mono or with a filter, and rule out any other mirror related issue, I suspect you will still see this problem on a cmos colour camera. Easy to correct in processing, so no biggie. 

I finally got around to finishing a proper take on M27. So far I have only had random shots, but this time I collected 13 hours of NB data on it.

19*1200s Ha bin1 3nm

20*1200s OIII bin1 8nm

RC12, ASA DDM85, G3-16200 from E-Eye during July. Processed in PI and PS. Comments  and suggestions welcomed.

I think they show exactly why I find the drizzles better. Very notably, the contrast is larger, because the dark areas are darker. 

3 minutes ago, Datalord said:

It is crazy good.

Case in point. Tonight's guiding session at 2400mm FL.

I'll post a +1 to all of what Dave and Waldemar said and say that the software part of the DDM is the weak link. Once I eliminated the horrible Sequence software, I have found this mount to be the closest thing to magic this side of Harry Potter.

Like Dave mentioned, they stopped producing 60 and 85, so only hope for one of those is second hand and I since I can't see myself ever selling mine, I would be surprised to see anyone else do it. It is crazy good.

I do the same. As long as you get to positive temperatures, you should be good. Your aim is to prevent the glass from cracking by going from -30 to +10 too fast. As long as the temperature difference is not too big, you should be fine.

Anything within 10 arcmin will give you reasonably small pointing errors, which can be platesolved away. It's easily guidable and 3 arcmin is totally fine. Let it be, don't touch it until it is a problem in your image and enjoy not fiddling with your setup.

1 hour ago, Wavseeker said:

that being said i am leaning towards a xx12i for the following reasons.

- i can still take pictures of the moon if i want

With those reasons, I would tend to agree. And you can also take images of planets as they are best done with "lucky" video captures. But don't set your hopes up for deep sky AP, for that you need a very different setup.

Good luck with it!

More to echo what others have said. Drop the notion of AP for any of the scopes you are considering. The Celestron 6 has a focal length of 1500mm, which is really bloody long for a relatively flimsy mount on a wedge. Add to it that it is an f10 and you have to take at least 300s exposures to get good results and you have a recipe for disappointment.

If you want to go for AP in any sense, under heavy light pollution, you must have a large aperture, fast scope on an eq, shooting many short exposures. That can be achieved with a newtonian. This is not a simple instrument, but if you go for, say 1000 * 10s exposures, you can get really nice results and the mount doesn't have to be too accurate.

I'm not trying to put your dreams to rest, but merely setting expectations. Here's my very first picture from my celestron 6 evolution. I could probably process it vastly better today, but this is what you can expect to get as a complete beginner:

This image cost me a wedge and accessories to connect a camera to the scope.

6 minutes ago, Wavseeker said:

so in terms of portability and price per aperture which is best?

yes?

The question sadly makes no sense. Again, it comes down to what you want to achieve. Easy entry to the stars and visual? go for the dob. Affordable astrophotography? Small refractor and an eq mount. Those two things are not easily compatible.

20 hours ago, Wavseeker said:

- astrophotography becomes real accessible now

No, please don't go that route. I started with this exact system. You will then have to buy a wedge, which will get you to work, but it just doesn't work as well for photography as you will ever want it to. The evolution is the perfect compromise between visual and AP and thus it is equally useless for both. 😞

If you ever want to do photography, you have to get a decent eq mount whose precision matches your focal length. Longer LF, more precision, more expensive.