AstroMuni

On 25/03/2024 at 12:11, edarter said:

Correct Gain - How do I find out what is the correct gain to use? I did find another thread on here about the AA 26C which I think suggested gain of 200 as thats when the S/N ratio changed significantly.

One way is to look at the graphs provided by the vendor. As the ZWO ASI2600mc is using same IMX571 chip the graphs for this would be similar to the Altair version. These show a significant drop in read noise at Gain 100 when HCG kicks in.

On 24/03/2024 at 01:57, Astrotravelk said:

You're in Hampshire near me, do you know the Solent Amateur Astronomy group?

I live in North Hampshire, so a member of the Basingstoke society. We have a few members who also attend the HAG meetings, but I dont think I know anyone from Solent group.

18 hours ago, TiffsAndAstro said:

ill attach a couple of subs when i get home of what isn't acceptable which is aberation of the stars and/or tricky focusing.

Remind me, whats your equipment at the moment? Looking at your images they are certainly out of focus but at first glance this seems quite similar across the frame.

3 hours ago, Gerr said:

I did background extraction

Check out GraXpert AI too. Sometimes it does a better job at extracting the background as compared to RBF in Siril (btw, RBF is from GraXpert and incorporated into Siril)

On 15/03/2024 at 20:06, TiffsAndAstro said:

what sort of numbers are good enough? is there a chart somewhere of like focal length, exp time, guiding yes/no etc?

Its not just the PA accuracy that influences the image quality. There are other factors like mount stability, guiding, backlash etc.that affect your image. At the end of the day, its what level of quality is good enough (acceptable) for you.

On 30/12/2023 at 01:37, GrumpiusMaximus said:

The main problem is setting the time and having the patience to get it all set up.  At the moment I'm mainly doing visual astronomy.  I do want to get this all going though, looks really impressive going from you there.

Have you set  & saved your coords under the Geographic... option? Once thats done it should grab the right time from your wifi.

On 08/03/2024 at 15:31, scarlin said:

What do you think of pi 5 and the AstroArch distribution?

Its a good distro and is slowly but surely becoming more main stream. I tried it when it was in its first few releases and faced issues where the updates would break the OS and it had to be reinstalled from scratch. So as compared to Astroberry or Stellarmate its still in its infant stages but fast getting there all thanks to its maintainer...Hats off for his efforts.

On 25/02/2024 at 08:10, 900SL said:

Would  I need a coma corrector with small sensor cameras like an ASI 178 or 533?

You might just get away without one. I need a CC for the ASI533 with 130/650 scope.

On 09/03/2024 at 21:27, TiffsAndAstro said:

just trying to update my old macbook

As a Mac user you could also try Kstars/Ekos which runs natively on Mac & Linux based devices. This software also provides the tool for PA.

13 minutes ago, TiffsAndAstro said:

I'm on a phone atm and I'm old

Anyone who can use a phone to respond in forums is still young... ha ha 

17 minutes ago, TiffsAndAstro said:

Synscap app wont let me doing an in app polar alignment until it has mel maz values from a 2 or 3star alignment.

After doing a 2/3 star alignment the synscan app is trying to tell you how far off you are from a perfect polar alignment. If you find you are way off then start the process again (without using the hand controller). I wouldnt worry too much about it if you have visually checked the location of polaris in the clockface. I never get perfect PA and can still manage to get decent images without star trails. So dont worry.

8 minutes ago, TiffsAndAstro said:

so after doing a second pa i looked in information:

id=2'28.5' ch=00.0' np=00.0'

mel=00.1' maz=06.4 tilt=03,8'

This post may help https://www.cloudynights.com/topic/639135-synscan-goto-alignment-precision/

2 minutes ago, TiffsAndAstro said:

I posted my mel maz

Sorry, whats this??

@TiffsAndAstro  The advice above makes perfect sense to me, but as its causing some confusion in your mind lets  keep it simple & try this again from scratch....

- To align your polarscope reticle try this https://www.myastroscience.com/polarscopecalibration

- Do NOT use your handcontroller for these steps

  - Position your mount so that Polaris is visible in your polarscope

  - Rotate the axis until the clockface is right side up (i.e 12 or 0 is up and 6 is down). Personally I am not fussed about the numbers themselves as long as it resembles a clock (eg. 3 maybe in 6 o'clock position)

  - Use the al-az knobs, latitude bolt until polaris is in the right position in the clock face. You can get the location from any polar alignment app on your phone

- You can now start using the hand controller to do star alignment etc.

DO NOT move your mount or adjust any knobs after doing star alignment!

Hope this makes sense 🙂 

1 hour ago, B4silio said:

So I was wondering: what free software (or software combinations) would allow to do the same alignment without having to use ASIAIR or SharpCapPro?

NINA (for windows users) and Ekos (for Mac/Linux/RPi users)

1 hour ago, B4silio said:

but I haven't found a "Polar align with plate solving" solution in the couple of software I've actually tried.

Ekos certainly does this.

20 hours ago, TiffsAndAstro said:

This is fantastic ty.

Parallax is a really good word to describe the effect I can see happen. In case it helps, if I try to look to the far extreme right I can see I little column of years. A bit like:

2026

2025

2024   .......

2023

However I'm so pro at this I thought there was only one ring to adjust polar scope focus. Will need to look for the plate thing you mention

Looks like you have a similar reticle to mine. If you look closely you will notice 3 circles in the clock face. The years tell you which of the circles to use for aligning Polaris. At the moment its the central ring. I wouldnt worry too much about parallax error. I have been doing polar alignment using the polarscope and my images havent been badly affected using exposure times between 30-60s without guiding. Good luck.

Also play around with this tool https://astronomy.tools/calculators/ccd_suitability

to see which camera is best suited for your scope. Assuming you have already purchased this scope, the FL is 750mm so the only variable factor is pixel size. A lot of modern cameras have pixel sizes between 2.9-3.75um and you can see from the calculator that getting a camera with 2.9um is more favourable as you can also bin 2x2. Ultimately I think its your budget that will help decide which camera to go for. I started my AP journey with an ASI224mc.

29 minutes ago, tomato said:

Or get into mosaics, not $$$$$$ but tttttttttt.😉

ttttt = Lots of tomatoes working together? 😉

46 minutes ago, Stickey said:

Each telescope/lens and camera combination will have a fixed AoV.

My understanding is that the telescope/lens will dictate the FoV. The camera sensor can only limit this view (assuming the sensor is not large enough). So in the examples below, for the same scope you could get larger sensor cameras and get more of the object into the view.

5 minutes ago, ollypenrice said:

You just need a bigger square sensor...$$$$$$$$ 

Or a focal reducer $$$ 🙂

On 19/02/2024 at 18:17, AshleyCUK said:

thanks, i'll try that next clear night

You could still do that with the images you have gathered, dont have to wait for clear skies 🙂

1 hour ago, M40 said:

My current percentage has got to be 99% thinking about it and 1% doing it.

Thats definitely the situation due to the weather here 😞 and by the time I get to the stage of going out and setting up the scope my planning is out of date !

6 hours ago, Kilohertz said:

Anyway, I was just wondering if any of you are in the same boat, completely frustrated with the whole image capture process? I know live observing hasn't changed much but I'm getting too old to be standing around stooped over a scope in -10 weather.

Technology has helped me a lot in this regard. I have an RPi sitting outside in the cold and I can remain inside the house remotely accessing it. This would not have been easily achievable (say) 10 years ago, if at all.

9 hours ago, MannyT said:

I'm including 120 minutes stacked (10 seconds/each) picture and processed picture with Siril. 

Thats a great image.

On 18/02/2024 at 12:04, Astrotravelk said:

So, it doesn’t matter how it is polar aligned as long as it IS by the time to find an object and start imaging - and Stellarium will track once I’ve selected until I decide to stop. Great, roll on the clear skies! 

Suggest you get familiar with tools such as NINA which can assist with polar alignment, imaging, managing the mount etc. If you are a Mac user try Kstars/Ekos.

On 09/02/2024 at 09:40, doublevodka said:

f you have an older type with only Vixen compatibility, then you might need to purchase a Vixen dovetail bar, for example - https://www.firstlightoptics.com/dovetails-saddles-clamps/celestron-cg5-vixen-style-dovetail-bars.html

Or purchase https://www.firstlightoptics.com/sky-watcher-mount-accessories/sw_heq5_dual_saddle.html

🙂

17 hours ago, ONIKKINEN said:

Place samples manually in empty spots, not on stars. Not too many samples either, Elp suggested 20, which sounds good to me but you dont always need even that many.

And if you cant be bothered to manually place the markers, use GraXpert AI 🙂

In fact I recommend using this when you have a lot of nebulosity. It does a much better job than RBF.