alacant

Hi everyone

Not much 130pds activity recently so, here's one from the current heatwave in south eastern Spain. We found some blue bits in the sea of red, aka Cygnus.

Thanks for looking and heat or no heat, don't forget your humble 130s.

ngc6914 apil siril 1.3.0a proc st 1.9.588b ~4h uhc

Hi

So long as you understand what the script is doing, enabling you to troubleshoot should anything go wrong, and the results are acceptable to you, then perfect.
OTOH, using Siril manually takes only a few more clicks, plus you can use methods -such as our minimalist approach- for which there is no script; the operator is in control rather than the script.

Cheers

17 hours ago, FenderGreg said:

What’s the advantage of calibrating, registering and stacking the images yourself?

Which alternatives did you have in mind?

11 hours ago, bomberbaz said:

exclusion of darks

Hi

Unless you have a camera which has sensor amplifier glow, we find that dark frames introduce more problems than they solve. That, added to the fact that with many cameras it is not possible to match the temperature of the dark and light frames leads us to the simplified approach. Perhaps best to try both and see which you prefer. No two cameras are alike so generalisations only go so far.

11 hours ago, bomberbaz said:

can you explain 2 pass

NP:

But as @AstroMunirecommends, a bit of rtfm goes a long way.

Cheers and HTH

22 hours ago, FenderGreg said:

siril 1.3.0??

Everyone can help by testing:

Latest git here.

22 hours ago, FenderGreg said:

Did you use background extraction in Siril?

We use Siril only for calibration, registration and stacking.

If you really do need to use bg-extract, simply put the points manually yourself to coincide with a few reasonably dark and well spaced patches. With a UHC, you'll probably find that you don't need to.

22 hours ago, FenderGreg said:

but only got just over an hour n half before a storm

Aww, pity. At this game, you need patience.

Cheers and thanks for your comment

3 hours ago, AstroMuni said:

process flow in Siril

The simplest possible.

Calibrate: light and flat frames offset removal only. No automated scripts. No darks. No extract Ha-Oiii stuff. No star processing or any other distraction. No nonsense!
Register: two pass 
Stack: sigma low 5 high 2

That's it. Cheers and HTH

Hi everyone

Along with our cheepo UHC filter, this was doable probably because the moon was low toward Sagittarius. Unfortunately it flares bright stars toward the edges. I'm told I need to get the filter in front of the sensor, rather than on the telescope side of the cc. It's never straightforward...

Not keen on current processing trends; IMO, stars make the image. Leave them out and the image looks flat, lifeless...

Thanks for looking and do post your uhc images, especially if you had a go at full moon.

pn208 ~3h apilado: siril 1.3.0a. proc:st 1.9.557 hoo  oiii en nbaccent

On 26/06/2023 at 17:37, chubster1302 said:

even more complicated

Really? Entering;

=600

into the bias field is more complicated than taking and processing and a sequence of non temperature matched dark frames?!

19 hours ago, Albir phil said:

I wouldn't really know what kind of problem led may cause

Hi

Unless you're directly below one, I think you're going to be pleasantly surprised. The light-up-the-sky lamps of old have been replaced by well designed low energy versions. The moon is likely to form far more of a challenge.

Here's a worst case scenario; shot from around 10km north of Alicante a few days before San Juan. Yes, there's contamination, but hey, it's not bad.

... but with modern gradient removal algorithms, a few taps and you're ready to process.

If you really are troubled by this, you have access to a very low contamination zone looking south east over the Mediterranean: the beach😉

Cheers and HTH

18 hours ago, Albir phil said:

combat this problem 

Hi

What problems are you having?

Cheers 

1 hour ago, chubster1302 said:

Still do flats though,

Yes.

1 hour ago, chubster1302 said:

I dont know what that means.

https://siril.org/tutorials/synthetic-biases/

HTH

1 hour ago, chubster1302 said:

Dark flats

Hi

Keep it simple...

D5300, so best to lose any type of dark frame. Noise will be better controlled simply by subtracting the offset; Nikon NEF usually set 600 . Don't bother with in-camera bias. 

We recommend Siril for all calibration and stacking.

Cheers and HTH

Hi everyone

Given that spacing an unknown ff on a cheap refractor in the dark wasn't frustrating enough, I decided to complicate it still further by adding the latest AliExpress UHC to the mix. So, here we are with a 72ed, an undocumented ff and an -optimistically named- angeleyes uhc filter Apart from obliterating most of the stars, the combination seems to work. The optical struggle is outlined in this thread.

Thanks for looking and clear skies.

Hi everyone

We began the trial and error last night. Forget the customary 55mm.

We got as far as 66mm ff to sensor.. It's tilted -the darn flattener has an undercut- so it's useless with a compression ring. Have been trying unsuccessfully to find the whereabouts of the original collar without the ring. At least the stars seem roundish.

Tilt apart, it seems to be an improvement over the three-element, false colour at the extremities has gone and the stars are well controlled. I don't know if I have the patience to do another session of screwing-unscrewing-dropping-fumbling,

Anyway, here's what it's like over aps-c. It plate solves to 345mm.

On 29/08/2022 at 10:25, GalaxyGael said:

the 4 element one

Hi

Long shot, I know after so long... Does anyone have the spacings for the 4 element version?

Apologies in advance for the noise; duplicates this:

Thanks again

Unfortunately, it's the backfocus distance I'm missing. The three element version came with suggested backfocus distances. These depended upon the focal length of the telescope in which they were deployed. I copied those distances here:

The new version has nothing; I was handed a box devoid of any hint of instruction. Maybe the best plan is to assume it's the same as the old version and begin with a backfocus of around 65mm, point at Cygnus and hope it doesn't take all night to nail it.

Cheers

Thanks

Is the 55mm with the supplied 8.5mm collar in place?

TIA

Hi everyone

I'm hopeless with refractors. Has anyone experience of these?

What bf should we use for a 72ed -fl 432mm- and is that with or without the 8.5mm ring pictured?

TIA

On 11/06/2023 at 21:54, Marvin Jenkins said:

Anyone else done anything similar?

My boss asked me to look up 'Pacman Nebula' in Burnham. Yeah, it took me a while too...!

Hi everyone

Surprising how the star field changes moving toward the mw. Tried to stick to the same processing, but m29 was so awash with background stuff, I lost a lot of the battle. Probably not how to do it but anyway...

 Change from 200mm to 150mm some time after 01:00. Recommendation: don't do that. I speak from bitter fumbling-in-the-dark experience!

Thanks for looking and do share your versions if you've had a go at any of these.

m56, gso203

ngc6819, nt150s

m29, nt150s

On 14/06/2023 at 23:55, chubster1302 said:

not really sure what to do from here

Hi

If your images are ok, perhaps best to leave it as it is. 

If not, maybe post an example, along with the logs with which it is associated. We then stand a much better chance of being able to help.

Cheers

Hi

If you've ever dismantled a new sw mount, you'll know of the horrors within; performance issues will become less of a mystery. When you've reached the stage where you're still not satisfied with the images...

Suggestions to move on from here:

- clean, re-grease and replace the cone bearing at the base of DEC taking care to pre-load it with just sufficient torque that the axis spin smoothly. That may just do it. Even better...

- dismantle the whole of DEC, clean, inspect, smooth -very fine emery- where necessary and replace the bearings with known performance equivalents. SKF are a little more expensive but more likely to be within specification than those currently in place. 

- Still no good? Repeat for RA.

The dismantling and bearing part number details are covered here. The only gotcha we'd add on newer 6Rs is to place the axis shafts in the freezer for an hour or so before attempting to refit through the new bearings. The worm shafts are not however interference so are easily pushed into -even SKF-  608s at ambient.

Cheers and HTH

The 4/3 gives you an extra 20mm or so, so that may just do it. Otherwise you're going to need a threaded Barlow and/or a low profile t- adapter.

This may be a good point to go along to your local astro club who armed with a box full of adapters, will get you focussed within a few moments of arriving;)

HTH

1 hour ago, Diver99 said:

T adaptor and screws straight on to the focuser tube

So you're still ~10mm too far out. If you don't want to use the low profile adapter, you'll have to go to:

Camera > t-ring > barlow, leaving out the nosepiece.

Your Barlow should have a t-thread, enabling it to be screwed into the t-ring camera side and clamped into the focuser, telescope side:

Why not post a shot of your focuser from last night with the camera attached? We can then maybe help further.

Cheers and HTH.

On 05/06/2023 at 11:06, Diver99 said:

Nikon DSLR

Hi

- lose the Barlow, t-adapter and nosepiece.

- screw this adapter onto the telescope focuser:

 https://www.opticstar.com/Opticstar-Nikon-style-Low-Profile-T-Ring.html

- attach the camera to the exposed bayonet.

HTH