The "No EQ" DSO Challenge!

[kevhatch]

Sorry to hijack the thread - I have a Skywatcher star discovery 150p goto which I bought as my first scope with the intention of trying astrophotography after a while of just viewing (the blurb in the description said it was good for AP). I've had the scope now for two years, the last year trying and failing to get any decent pics. 

I've since read about the failings of the scope for AP but as some have said on here it is possible. I'm not willing/able to make the changes to the scope to get prime focus and don't really want to get a whole new setup.

After all that waffle .... I'm thinking of maybe buying something like - Skywatcher Star Travel 120-T or a bit more pricey - Skywatcher Evostar 80-ED DS .. Could I use either of these on the mount I already have? Or any suggestions welcome.

Thanks

Kev

[happy-kat]

Hi

I would look to use just a camera and camera lens on the mount. Many DSO are pretty large and they're is a lot of milage from a camera a and lens.

[kevhatch]

12 hours ago, happy-kat said:

Hi

I would look to use just a camera and camera lens on the mount. Many DSO are pretty large and they're is a lot of milage from a camera a and lens.

I hadn't considered that, with the price of decent lenses isn't it getting near the cost of a new rig?? What size of lens would you recommend?

[alacant]

15 minutes ago, kevhatch said:

isn't it getting near the cost of a new rig?

Hi

No. OTC, you don't need anything fancy for AP. Some of the old manual lenses produce superb results.

A quick eBay throws this and this amongst hundreds of others. You'd also need an adaptor.

HTH

Edited June 30, 2019 by alacant

[happy-kat]

I like to use a T ring and T mount and shorter focal length say from 40mm to 100mm. I would look either at a prime vintage M42 lens my Ashai 55mm f2 is pretty good wide open and cost around £25 plus adaptor £10 M42 to EOS as I use a canon lens. 

What camera do you already own?

[kevhatch]

2 hours ago, happy-kat said:

I like to use a T ring and T mount and shorter focal length say from 40mm to 100mm. I would look either at a prime vintage M42 lens my Ashai 55mm f2 is pretty good wide open and cost around £25 plus adaptor £10 M42 to EOS as I use a canon lens. 

What camera do you already own?

I have a Nikon D5300.

[happy-kat]

M42 fit lenses will not work on your Nikon. Why not start by using the kit lens that came with your camera. 

[kevhatch]

2 minutes ago, happy-kat said:

M42 fit lenses will not work on your Nikon. Why not start by using the kit lens that came with your camera. 

Just my luck!!!

[catalinc]

On 31/12/2016 at 11:38, SteveNickolls said:

happy-kat,

Here's my way of mounting the Canon camera, I use an L bracket and a ball joint to provide very accurate alignment with the finder scope. I use a quick release plate too. The attachment piece between the camera hot shoe and finder scope works very well. I've found there's no re-alignment needed at each session as I dismantle only the quick release plate separating camera from the L bracket on the mount. I haven't experienced any issues with balancing the camera and that's even been when using the 75-300mm lens shown.

I have recently purchased BYEOS so can control imaging from the laptop set up in the kitchen overlooking the imaging spot. I've also sent off for cables to extend the length of the hand controller wire to the mount. I will then have the ability to nudge objects to get best framing. I've found BYEOS to be very useful enabling multiple stacking of Live View to better see fainter objects in almost real time. BYEOS also means I get to keep a watch on each downloaded frame so don't get caught out by dewing or clouds anymore. Oh, for a touch of low tech I add a hand warmer beneath the camera lens using an elastic band and it has kept dew away.

Here's to clear, dark skies.

Cheers,
Steve

 

Hello, finding your interesting assembly by chance, by looking to build something similar for my Canon and SynScan AZ mount

Would you mind if I ask you the details about the components? 

 

Thanks in advance.

Best Regards,

Catalin CACIULEANU

[happy-kat]

This is the L bracket in Steve's photo.

https://www.firstlightoptics.com/alt-azimuth/skywatcher-l-bracket-dovetail.html

Ball head is any camera ball head with suitable pay load, I got one on amazon that can take 8 kilos for about 15GBP. Though I now use a dove bar instead with a camera quick release plate attached as this provides better balance on my mount.

I use a red dot flash shoe finder base, you'll find a suitable finder base on ebay or similar mine looks maybe 3d printed. I can use this to align for the go to when using the camera as that was what I had. Perhaps you can find a flash shoe mount for the finder you already have with your telescope.

Edited July 1, 2019 by happy-kat

[kevhatch]

On 30/06/2019 at 18:17, happy-kat said:

M42 fit lenses will not work on your Nikon. Why not start by using the kit lens that came with your camera. 

I think I will probably go this way .. https://www.amazon.co.uk/Tamron-AF-70-300mm-4-5-6-Macro/dp/B0012UUP02?ref_=fsclp_pl_dp_1 .. with an L bracket and ball mount. At least I can use it with the camera for "normal" photography if it's no good for AP, and cheaper than a new set up! I'd better start saving a bit harder.

 

[Nerf_Caching]

Here are my first ever attempts at dslr astrophotography with a scope. From top to bottom:

M4, 6x30secs@iso 800 w/ 3 dark and flat frames.

M19, 24x30secs@iso 800 w/ 7 dark, flat and bias frames.

M9, 16x30secs@iso 800 w/ 7 dark, flat and bias frames.

All of these were taken with a Canon 650D dslr attached to a Skywatcher evostar 72ED OTA, mounted on a Nexstar 4/5SE mount tracking in alt-az mode.

Edited July 2, 2019 by Nerf_Caching

[catalinc]

22 hours ago, happy-kat said:

This is the L bracket in Steve's photo.

https://www.firstlightoptics.com/alt-azimuth/skywatcher-l-bracket-dovetail.html

Ball head is any camera ball head with suitable pay load, I got one on amazon that can take 8 kilos for about 15GBP. Though I now use a dove bar instead with a camera quick release plate attached as this provides better balance on my mount.

I use a red dot flash shoe finder base, you'll find a suitable finder base on ebay or similar mine looks maybe 3d printed. I can use this to align for the go to when using the camera as that was what I had. Perhaps you can find a flash shoe mount for the finder you already have with your telescope.

Great, thanks a lot.. Looking forward to get a nice photo of M13 with that 🙂.

[Filroden]

On 02/07/2019 at 10:29, Nerf_Caching said:

Here are my first ever attempts at dslr astrophotography with a scope. From top to bottom:

M4, 6x30secs@iso 800 w/ 3 dark and flat frames.

M19, 24x30secs@iso 800 w/ 7 dark, flat and bias frames.

M9, 16x30secs@iso 800 w/ 7 dark, flat and bias frames.

All of these were taken with a Canon 650D dslr attached to a Skywatcher evostar 72ED OTA, mounted on a Nexstar 4/5SE mount tracking in alt-az mode.

I wish my first attempts as astro-photography were so easily recognisable as astro-images! Well done. It gets better and easier from here

Your M9 is much sharper than your M4. Did you do anything different?

I'd recommend not using low numbers of darks (if at all). Unless your camera is cooled, darks could add more noise than they remove. Even if your camera is cooled, using only a small number of darks could likewise introduce more noise. I'd recommend taking 25-30 darks if I was using them as you can use better statistical rejection algorithms to combine them.

I'm also not sure that your flats are fully working. You seem to have light pollution gradients (not surprising in HK) but they show the classic vignette of an image that has not been fully corrected by flats.

What processing software are you using? There may be ways to improve the flat correction and remove the light pollution.

[Nerf_Caching]

3 minutes ago, Filroden said:

Your M9 is much sharper than your M4. Did you do anything different?

Not that I know of, no. All of my images went through the exact same process: Stack in DSS along w/ calibration frames then transfer to GIMP for processing.

BTW, I only know very little on post-processing based on other youtube tutorials, so any help with removing gradients and stuff would be greatly appreciated:)

Edited July 3, 2019 by Nerf_Caching

[Nigel G]

On 02/07/2019 at 10:29, Nerf_Caching said:

Here are my first ever attempts at dslr astrophotography with a scope. From top to bottom:

M4, 6x30secs@iso 800 w/ 3 dark and flat frames.

M19, 24x30secs@iso 800 w/ 7 dark, flat and bias frames.

M9, 16x30secs@iso 800 w/ 7 dark, flat and bias frames.

All of these were taken with a Canon 650D dslr attached to a Skywatcher evostar 72ED OTA, mounted on a Nexstar 4/5SE mount tracking in alt-az mode.

Excellent first attempt, great looking stars. 

 

4 hours ago, Nerf_Caching said:

BTW, I only know very little on post-processing based on other youtube tutorials, so any help with removing gradients and stuff would be greatly appreciated:)

Have you tried Star Tools ? great post stack processing software, unlimited free trial.

https://www.startools.org/

Nige.

[mackiedlm]

Hi folks,

New on here and just a very few months into astro-imaging. Found this thread while looking for some ideas on what I could hope to achieve with;

Meade 8" LX200 GPS,

Standard forked alt-az mount - autostar GoTo

f6.3 focal reducer

Unmodded Canon 1100D

Attached my very first two images teaken this spring. I have  long way to go I know but in keeping with this thread it shows that total newbies can do something with the equipment they already have.

M104 was 21  X 60s @ ISO1600 (Low in the west so minimal field rotation)

M13 was 30 X 30s @ ISO1600 (relatively low in the east for the same reason)

Full sets of calibration frames applied to both

Stacked in DSS, processed in Photoshop.

I'd really appreciate any comments/suggestions on how these could be improved with the equipment listed above.

David

[The Admiral]

Hi, and welcome to the thread.

I think they are very good for someone just getting into the 'art', and I agree it just shows what can be achieved with Alt-Az imaging. I was going to say 'with basic equipment', but your Meade is hardly that ;<).

Your stars are sharp and round, and there's nice colour in M13, blue to gold, with detail to the core. My only comment is that the sky looks 'very' black, which suggests perhaps you could do with raising the black point a little. That of course might reveal more noise, but more subs will always help there.

How many darks did you use? There is some debate about using darks with DSLRs, but if you do, certainly a good number is required otherwise they can introduce more noise. Something to bear in mind.

Ian

[mackiedlm]

Hi Ian, thanks very much for the comments - they are encouraging.

To be honest the "very black" background is more because I just like it that way. Everything Ive read suggests setting black point to around 15,15,15, to  25,25,25 but for me that comes out looking too grey. But that may just be me or my monitor! But i'll have a go at moving the BP up a bit and see how that looks. Do you think I should just do that on what is currently my final image or should I go back to first stacked tiff and take it from first steps again?

I do find that my images can get quite noisy as my processing goes on and I have a low tolerance for noise unfortunately. Could you point me to any threads about the debate on using Darks with DSLR's because I was not really aware of that.

On the M13 I had 22 darks and 15 each of Flat, dark flat and bias for 30 lights.

On the M104 I had 20 darks and 15 each of Flat, dark flat and bias for 21 lights

On both image runs I discarded quite a lot of light subs (30%+) for distorted stars (seeing, i think, and some tracking errors) and then ran out of time because of he need to limit field rotation. What number would you be advising for darks (and other calibrations frames) for these types images.

Thanks again, I appreciate your help.

rgds

David.

[The Admiral]

2 hours ago, mackiedlm said:

Do you think I should just do that on what is currently my final image or should I go back to first stacked tiff and take it from first steps again?

Presumably you stacked the RAWs and ended up with a FITS/TIFF from DSS. You need an image in which data has not been thrown away or locked in during the editing process. For that reason you shouldn't re-process JPEGs, particularly as they are only 8-bit and are not lossless, and you need 16 bits as a minimum. I'm not sure about PS, because IIRC the data is frozen in after each processing step. Perhaps a PS user could comment here. RAW processors, like Lightroom for example, always apply the processing steps from the beginning on the RAW file, so if you change the processing, then the result is always a new process on the original RAW. PS may remember the steps, I don't know. Don't get me wrong, I'm not recommending LR for astro processing, but it is useful in tarting up (sorry, polishing) your final image.

You could have a look at StarTools (https://www.startools.org/), and although the processing is approached differently to other applications, it is relatively cheap and the trial version is unlimited except that you can' save. If you are used to PS though you might find it too 'cloak and dagger'! Worth a look though.

2 hours ago, mackiedlm said:

Could you point me to any threads about the debate on using Darks with DSLR's because I was not really aware of that.

I can't point you to an individual thread, but a search would find plenty. In the the process of subtracting the darks , the noise is combined, so you will end up with a result which contains both the noise of the image and the noise in the dark. So you want to reduce the noise contributed by the darks to a reasonable level (you can easily control that) and the way to do that is to do a lot of them. I typically did around 50 of them, but 20 might be considered OK. Each to his own. The other important issue though is that the background noise is very sensitive to sensor temperature, so unless the darks are taken at the same temperature they may not be representative. This can a big problem with DSLRs where the sensor temperature is not controlled. Not only that but camera manufacturers go to some lengths to subtract noise before committing the RAW to file, so the noise behaviour can't be easily ascertained. Having said all this, with Alt-Az imaging and short exposures, you may not see any difference. I've both used darks, and just replaced the master dark with the master bias. If you have significant sensor unevenness, such as from amp glow, or a large number of hot pixels, you may have to do them however.

Yup, discarding subs because of trailing is a problem! Fact of life I think, so you always need to do more than you think .

Hope that helps.

Ian

 

Edited July 4, 2019 by The Admiral

[mackiedlm]

Thanks Ian, that is all really helpful.

Yes I save as 16 bit/ch tiff from DSS. Because I'm so new at processing these astro-images I'm saving down my PS work in progress with all layers, including adjustment layers still in place. Takes up a ton of hard drive space but it allows me to go back and tinker when I get suggestions like yours. Finaly I flatten the image and save a final tiff then do a seperate JPEG. So I'll go back to the last file I have with everything still there and see how that goes.

I have StarTools and have done a few good adjustments with it but I found I was just pressing buttons and not understanding what I, or the programme, was doing to the image so it ended up very hit and miss. I sometimes came up with a pleasing image but really now idea how I'd got there or how to get there again. So I went over to PS because I found there was much more available in terms of tutorials and direction. That said I still occaisionally throw my final Tiff into StarTools, press a few buttons and end up with something better than I started with! 

On the darks,  I've just gone back and looked at my data and see that there may be 2-3C of a difference between my lights and darks (darks are lower because they were done after the lights - later and colder). Do you think that would be enough to be casuing a problem?

Anyway, all great information which I'll feed into my next imaging session - when it finally gets dark again here.

Thanks again, David.

 

[Manners2020]

Whirlpool, trifid  and eagle.  Rare night with a visible sky last night.  All three were 72×10 seconds exposures with 20 dark and 20 light frames.  First time I've seen these two nebulas  so I was thrilled to catch them. 9.25 nexstar evolution @f 6.3 with an asi294 mc.

Edited July 31, 2019 by Manners2020
Typo

[happy-kat]

The whirl pool is great, I'd love to see what you could pull out of that target if you hit it with 200 odd light frames. Dark flats are quick to take why not add those and bias files to your calibration files.

[Manners2020]

That's  the plan but it will have to be a different  time of year.  It was literally  inches above my neighbors  roof.   I always get a much harder sky colour tobdeal with when I'm shooting to close to houses.  Thanks though , that's the most detail I've ever had from that one.

[Manners2020]

The darks and flats were in there. Probably  not enough though and my flats were ones I used from a week before. I wasn't convinced they were doing a good job. Heres a question about flats actually. ... so the focus is supposed to be the same as the lights but does that mean actual focus or the distance  of the image train being in the exact position  to the corrector  plate as the lights.. you know with focus shifting slightly and the rest of it?