Need help with my step by step instructions please

[ianpwilliams]

Ok thanks.

I'll test the camera remote indoors without the camera and see what happens.

When it says "2 stars on the SAME side of the meridian", that made me wonder if choosing stars on BOTH sides of the meridian might be required and/or produce better results. And yes I'm referring to the 2-star and 3-star alignment processes on the SynScan handset.

And as my instructions say to do 3-star once and then 2-star multiple times, I wondered if changing the two star for 2-star might also be required and/or produce better results, but it sounds like it doesn't matter.

[ianpwilliams]

Ok thanks.

I'll test the camera remote indoors without the camera and see what happens.

When it says "2 stars on the SAME side of the meridian", that made me wonder if choosing stars on BOTH sides of the meridian might be required and/or produce better results. And yes I'm referring to the 2-star and 3-star alignment processes on the SynScan handset.

And as my instructions say to do 3-star once and then 2-star multiple times, I wondered if changing the two star for 2-star might also be required and/or produce better results, but it sounds like it doesn't matter.

Sorry, I meant to ask that if the stars for the 2-star should be on the same side, then would ensuring that at least one of the three stars for the 3-star alignment was on the other side of the meridian, then would that give better results.

[carastro]

Ian it has been my experience that if you use the synscan it will pick the right selection of stars for any given alignment.  I believe it chooses 2 stars on the same side of the meridian for a 2 star align, and if you choose a 3 star align it will cross the meridian for the 3rd star.  I don't know why you are having to decide which stars to choose yourself.

The more stars you do the more accurate will be the alignment if you're setting up each time.  If you have a permanent rig and don't move the mount, then you can get away with doing only a 1 star alignment, and if you use EQMod you can choose whichever stars you like.

Carole 

[ianpwilliams]

Ok thanks. I didn't know if it was maybe the case that the SynScan just listed every star that was available regardless of position, and that it was down to me to choose the best stars based on the target, meridian etc, but it sounds like the SynScan just takes care of all that, which is good to know.

[Tinker1947]

The better way to do PA with the handset is, do a 2 star align, then the PA, then a 1 star align, park to the home position, power down, the do it all again using different stars for the 2 star align and the PA star, one in the west and one in the east, this should get the MEL & MAS close to very good, this is better for a permanent set-up doing this on a nightly sett up would get a bit tiresome if we every had clear sky's 2 nights in a row. Getting the tripod feet in the same place every time would help but its not perfect....

[ianpwilliams]

Yes, it would be a bit of a pain doing that with a non-permanent setup! I have got my tripod feet, weight bar and and dove tail marked though (and I keep the legs the same length), which quickly gives me a level, balanced setup pointing at Polaris, which really helps. Hopefully my PA can get a lot more precise once I start using the laptop.

As for two clear nights in a row, at the moment I've got clear skies forecast for tonight and tomorrow. Here's hoping it doesn't change.

Edit: spoke too soon, just tonight it is then!

[carastro]

I didn't know if it was maybe the case that the SynScan just listed every star that was available regardless of position

You will find it will give you a different selection for each alignment star it wants you to align on, if you scroll down the choice of stars you will sometimes find there is not one on there that is recogniseable, but on other stars (normally the 1st star) it is one of the more famous ones.  So yes it gives you options of the most suitable stars for the alignment that you are doing.  If you make sure you have focus and live view on you should be able to see the alignment stars OK even if you don't physically know where they are yourself. 

Carole 

[ianpwilliams]

Well, are you using the method in my original post No 9? There seems to be some superfluous steps in your process now. Also are you using the Handset polar alignment or something else?

Yes I've removed those extra steps (I was mixing up different sets of instructions). Should save some time.

[ianpwilliams]

Only dilemma now is whether to try to improve M31, or or try to improve M45, or go for something new tonight!

[Davey-T]

Only dilemma now is whether to try to improve M31, or or try to improve M45, or go for something new tonight!

That's the trouble with starting imaging, it's tempting to dodge all over the sky, but I think it's worth it to see what's available with your setup then when you calm down you can go back and spend more time on them, speaking from experience here

Dave

[ianpwilliams]

I ended up going for the Pleiades again as it happens. I've attached a screengrab of the subs I took. The first one (the darker one) is a 30-second test shot, and the rest are 90-second shots (one or two with star trails, so I'll take those out). But Image 1418-1421 are "off-colour", basically because some clouds came rolling through. I'm assuming I might as well keep the 30 -second sub in the stack, but what about the cloud subs? I take it I should reject those?

Also, once I'd done my subs, flats and darks, I attempted to find a new target (first M31, then M101), to see if I could grab some shots of that too, because I'm assuming that I could have used the same flats and darks for the new target, with it being the same session, and the camera and focuser not having moved?

As it happens it didn't work out anyway, because I couldn't see either object. Once again I had fine-tune polar alignment issues, although it was strange because when I selected Pleiades it was dead on. Is it possible to be polar aligned in one direction but not another?

[carastro]

You're getting your target nicely centred.  M101 is very faint, I'd forget about it unless you are doing longer subs in a dark site.

M51 would be OK,  Rosette nebula would probably show OK.  As would horsehead, but all these things really need longer exposure to do them justice.  Also M42 should be an easy peasy one.  

Carole 

[ianpwilliams]

Would a guided setup in my back garden make the fainter ones more achievable? With no car, dark sites aren't possible for me.

Regarding Subs/Darks/Flats/Bias, are there any kind of ratios I should stick to? For example I've got 201 Bias, but is probably only usually take a maximum of 20 of the other three. So would 201 Bias be too much for a stack like that? Or can you never have too many of a particular type?

Also, I seem to recall (or maybe I misread) someone saying that it's not worth taking more than 30 subs, is that true? My sub length is limited unguided, but my number of subs aren't (well, they are limited by the size of the memory card, but I'm getting a bigger one).

[carastro]

I never do more than about 30 bias, flats.  Darks even less than that, normally only as many as I can manage.  No upper limit to lights.  

Guiding and longer subs would help with M101, but I live in the suburbs of London and even with long subs M101 is sitll rubbish from here.  

Carole 

[ianpwilliams]

Where do you think I could look for a list of realistic targets for my setup?

Also, could you possibly tell me what you did when you processed my Pleiades stack, so that I can try it myself in GIMP (and/or my dad's Lightroom)?

[Davey-T]

Subs look a bit orange, are you using a light pollution filter ? bit of a cleft stick though, you can get longer subs before they go completely orange but end up with a different colour cast to process out, on balance though I find a LP  filter helps.

Dave

[Tinker1947]

This program gives you a list showing what's in your night sky, set the filters and it will list what every you want to look at....

http://www.whatsup.ricksastro.com/

[wuthton]

Where do you think I could look for a list of realistic targets for my setup?

Also, could you possibly tell me what you did when you processed my Pleiades stack, so that I can try it myself in GIMP (and/or my dad's Lightroom)?

You should get stuck in to using PixInsight and/or Photoshop sooner rather than later. Gimp just doesn't cut it long term.

Harry Page (harrysastroshed.com) has done some excellent video tutorials for PixInsight.

[ianpwilliams]

Subs look a bit orange, are you using a light pollution filter ? bit of a cleft stick though, you can get longer subs before they go completely orange but end up with a different colour cast to process out, on balance though I find a LP filter helps.

Dave

An LP filter is fairly low priority at the moment (especially given how expensive they can get), behind a new powerful PC/laptop and hopefully PixInSight. But something to consider for the future though.

[ianpwilliams]

This program gives you a list showing what's in your night sky, set the filters and it will list what every you want to look at....

http://www.whatsup.ricksastro.com/

That's reminded me of the one I like to use actually, the black water toolbox. I'll check that with my equipment, and see what I can see. Although I don't know if that'll allow for my light pollution etc.

I hear the Whirlpool Galaxy is a viable option anyway.

[ianpwilliams]

Do you think I should include those four shots near the bottom of my sceengrab, which are the ones where some clouds came through? There is no star trailing in them, but I don't know if they would make the stack better, or worse, or have no effect. Same question goes for the 30-second sub at the top (which is a lot darker, being one third the length).

Also, would it be worth re-stacking my M31 sessions with 201 Bias instead of around 20? Or would that likely make no difference either?

[ianpwilliams]

Also, should I still be aiming for around 50 stars in the star detection threshold settings in DSS even if it means that the slider is at about 95%?

Edit: at 92% and 66 stars, it's now saying that only one frame will be stacked, and that I should change it to detect more stars. What should I set it to detect?

[ianpwilliams]

A bit of a Google search led to a thread on here saying that the DSS message means the subs are either out of focus or with star trails. I'm sure the focus is ok, because I used a Bhatinov Mask. I also removed the more obvious star trail shots from the stack, and I've scrutinized the remaining 13 shots close up, and if there is any star trailing in them, it's the absolute tiniest I can see. So I'm at a bit of a loss really.

[carastro]

Also, could you possibly tell me what you did when you processed my Pleiades stack, so that I can try it myself in GIMP (and/or my dad's Lightroom)? Also, could you possibly tell me what you did when you processed my Pleiades stack, so that I can try it myself in GIMP (and/or my dad's Lightroom)? 

I mostly used levels and curves in photoshop and gradient exterminator.

Carole

[ianpwilliams]

Ok.

Looks like DSSdoesn't like my second set of Pleiades subs, even though they look fine to me. I'll start a separate thread anyway to see if anyone has any thoughts on it.

It's very disappointing though. That's four sessions (2 x M31 and 2 x M45), with two failures, one because of atmosphere problems that I couldn't see, and one because DSS decides my subs aren't good enough. I'll need to know what my limits are (I'm guessing 60 seconds), because it really annoying when everything looks fine in live view, but DSS says no.