david_taurus83

30 minutes ago, assouptro said:

Hi David

I am not entirely sure what the FITS header is? I have been referring to the filename or the image properties but if there is more information hidden in the FITS that can possibly help I'd be interested in learning about it!

Cheers 

Bryan

The FITS header contains information like the exposure length, CCD temp, camera gain, your location, RA and DEC information, pixel size etc. Its pretty comprehensive. Each capture software has slightly different formats. I'm wondering if Artemis has put anything in there to indicate the rotation? I use Ekos for capture and Pixinsight for processing and both can display the FITS header. Do you want to post up a sub and I will look to see if Artemis has wrote anything into the header?

16 minutes ago, assouptro said:

That camera has an option to rotate the image 180 degrees which can be useful do alignment with a previous imaging session especially after a meridian flip, the problem is, if you forget to uncheck the rotate camera option then the subs will  be “upside down” in relation to your calibration frames. A flipped flat would be a flat taken with the rotate camera option checked so you can calibrate the frames taken “by accident’ the problem I have, as David kindly pointed out, is identifying the images that have been taken in the rotate mode as they look the same as images taken before the meridian. 
I hope that makes sense? 
cheers 

Bryan

Bryan, you say there is nothing in the file information. Do you mean the FITS header?

6 minutes ago, gorann said:

Now I am confused. What is a flipped flat and why would anyone flip a flat? If the camera has not be rotaded the flats would be the same before and after a meridean flip.

I have never used Artemis but it appears you can tick a box so the software will output the file rotated 180°.

I do use Pixinsight but if I understand correctly, Bryan doesn't know which images are flipped between either a meridian flip or the rotate 180° function in Artemis. So he cant calibrate as he needs to match the Artemis flipped lights with Artemis flipped flats, darks and bias.

As already mentioned, I think the best option is to manually inspect each sub and match the sub to a corresponding calibration sub with matching hot pixels.

1 hour ago, gorann said:

This is usually no problem at all if you use Pixinsight for the stacking (which I do before I start processing in PS). PI will automatically recognize 180° turned images during star alignment of the subs. What you do before star aligning your subs is the calibration of the "unturned" subs using a master dark, master flat, master bias, or whatever you want to use for the calibration (it is important that you do this on unturned subs so the chip is oriented the same way as in your calibration frames). So work flow is: Calibrate your images as they are now (so unturned) -> Star align them (called Image Registration in PI and they are automatically turned by PI in the same direction as the reference image that you have picked in your stack) -> Stack them into one image (called Image Integration in PI). If you have OSC data then you have to do debayering  after calibration but before star alignment.

Not quite sure I understand this. Star aligning will reference all images off a single frame. It will also move any dust bunnies and vignetting so cant be used to align the frames before calibrating.

It may have become misaligned when you were changing the scope over to the new mount. It happens and hopefully your last night out was just one of those nights where guiding isn't going to be great. I'll be interested to see how much your guiding improves. The AZEQ6 will quite happily guide to an average RMS of 0.5-0.6" but my peak errors typically are 1.0" to -1.0". Ok for my current focal lengths of 336mm and 564mm. I'd still like the bullseye to be a bit more concentrated but I suppose I'll have to live with it for the time being while I'm still setting up on a tripod.

Hi Alan. Did you clear calibration and run a new one for the new mount?

^^^ 15 minutes!

When I do polar align with Sharpcap the starting error was always around the same. Down around 5 arc minutes and left or right by a minute or 2.

I haven't polar aligned now for about 6 weeks and I'm using an AZEQ6 on a tripod that I take indoors after each session! I have 3 slabs in the garden that I have drilled a small hole where each of the tripod legs sit. I used to polar align each session with Sharpcap but a while back I was doing some testing and I just set up without aligning. I decided to try a few subs at the end so I just fired up PHD and started guiding. The average RMS error was no different to what it usually is if i aligned. So the next night out i done the same and got the same result. So I've been doing it for weeks now. Set mount up on the slabs, power everything up and plate solve my way to target and image. No polar aligning and no PHD calibration. My guiding RMS is typically 0.6" to 0.8".

To make my long story short, I'm saying you will probably find little difference in in your guiding result whether your mount is perfectly aligned or slightly out.

Incredible!

Are you using the internal guider or PHD2? Make sure the reading is in arc seconds and not pixels.

Also, make sure in the guiding tab that Ekos has selected the correct camera and scope.

Not sure how SGP works but Kstars records the last position of the focuser on each filter and restores it to each position should you choose to do flats after the lights.

If your filters and sensor cover are completely free from dust and the flats only show vignetting then you could probably get away without doing flats each session. Even if you have a few dust bunnies I find they tend to stay in the same place. But the risk is you could shoot 3/4 hours of great data and 1 spec of dust could have moved and you could end up with a wasted session. There have also been reports of the ZWO wheels not returning to the exact previous position of each filter, though I've not experienced this myself.

Unless the weather is playing up mid session, or I'm not too happy with the quality of the subs or im just too tired, I shoot new flats each session. The fact is we spend so much on all the kit to get so little time to use it because of the weather, I personally think taking flats is a price worth paying each night.

https://stargazerslounge.com/topic/334568-setting-up-platesolving-in-astrophotography-tool-apt/

APT, made for Canon and its FREE! But worth paying the optional 18 euros as it's a great bit of software.

13 hours ago, souls33k3r said:

I have come to a point where I'm finding spacers are now sort of feel like they're welded together rather than tightened and they are absolutely hard to unscrew them. I've tried everything and have managed to loosen up a few of them but there are still quite a few that I can not seem to do much about. 

Now these spacers range from 2mm and all the way up to 15-20mm so am looking for something that will work on both small and big spacers. I know there are these these camera lens filter removal tools (I'm sure these will grip fine on thin spacers as well as thicker ones but not sure if they will grip tight enough?) 

And then you have these rubber strap wrenches (The rubber straps have thicker profile so not sure if I will be able to grip the thinner spacers? Say I have a 5mm and a 7mm stuck spacer stuck together, will this be better?) 

Not sure which one is best for the job keeping in mind I will be working with thin and thick spacers. 

Which one will works best and would you recommend and have used? 

Thanks in advance. 

Snap! I've just bought a set of the rubber straps. Not tried them yet..

As explained in the other thread, I had to use a small vice and apply a heat gun to get a 5mm spacer of a filter drawer the other night, hence the scoring on the spacer.

I'm also having a hankering for trying out a CCD. I got my ASI1600 a year ago and it's been very pleasing after starting with a DSLR. However, I tend to go against the grain of all the short sub hype and shoot much longer subs. Currently 900s with an Ha 7nm. I tried 20 minutes the once and it was even smoother than the 15 minutes but I didn't want to shoot another set of darks at the time. Also, I shoot RGB at around 3/5 minutes. I tried 30s subs the once and it was a bit of a pain to pre process and I messed up the last few hundred subs because of a wrong gain setting!

Been thinking about an Atik 460 as it still has smallish pixels and a decent sensor size. Should still cover a lot of objects with my GT71 at 336mm.

So, has anyone started mono with a CMOS and then made the switch to CCD and never looked back? Or has anyone regretted going CCD and switched to/back to CMOS with no regrets? (I couldn't justify keeping both, the ASI would have to go to fund the Atik)

21 minutes ago, johninderby said:

I used one this aft to remove a stubborn SCT diagonal with zero damage. 👍🏻

Also usefull for unscrewing lens cells, focusers etc.

I had to employ the use of a vice and a heat gun to undo the spacers from a filter drawer the other night. The 5mm is an absolute swine as it's so hard to grip. I dont even tighten them up much but they always appear to be welded upon removal!

How the hell are these astro related? Can anybody guess?!

Ok. Just let me know if you need the 5mm spacer and a few steel shims. Got plenty here 👍

19 hours ago, alan potts said:

I am not totally sure dave, The back space onthe reducer info states 55mm to the sensor. This is as you know I am sure is taken up with Zwo 21mm and 16.5mm spacers but doing this there is no way I believe I can get a IR/UV filter in the light path . The front of the reducer is a large size way over 2 inch filters, I think it is M68. On the other end is the normal M48.

Now as the Zow 16.5mm part is the only one of the 2 that has M48 thread I guess it's the filter thickness minus the 21mm sleeve.

In truth this isn't really a solution as I don't look at a filter and think That's Solid  I imagine I really need a purpose built filter draw or wheel ( where does ones stop, RGB&L filters, 1600pro etc) I don't really see an easy option Dave.

Alan

I think I know what you need. A 15mm filter drawer on the back of the reducer, 16.5mm M48-M42 spacer and your camera has 17.5mm to the sensor. This gives you 49mm leaving you 6mm short. You only need a 5mm spacer and 1mm of shim to make up the difference. I'm sure I have a 5mm spacer and some shims you could have. You would just need to source a 2" filter drawer. TS do one or 365 Astronomy is the UK supplier I got mine off.

https://www.365astronomy.com/ts-optics-filter-quick-changer-for-2-filters-m48x0.75-thread-length-15mm-including-filter-drawer.html

Hi Alan

What size spacer do you need? M42 or M48? I have a box of bits I can have a rummage through, perhaps a spacer in there I could send you?

2 hours ago, Adam J said:

Actually as its so close to the optical element and further spaced from the sensor then it would be in a wheel you might actially want to use it that way around anyhow as that way the AR coating is pointing towards the optics. Usually the other way but here I think the normal rule may be reversed. 

Adam 

I have always understood that Baader mounted filters have the AR coated side facing the optics, on the female threaded side of the filter cell.

2 hours ago, fwm891 said:

Then keep swapping it back to use on something else - easier to use a male/male adapter.

Agreed, but if used in a filterwheel the spacing might not always work.

8 hours ago, fwm891 said:

Ideally it needs a short male to male adapter so the filter can be inserted the correct way round as the female side of the filter should face the sky...

 

You could always try and unscrew the retaining ring that holds the glass in place and flip it round? The 1.25" Baaders all look to have a ring with notches. Would just need to use some careful persuasion.

@Skipper Billy just a thought, maybe your 2" OIII can be flipped around?

Try the original data again but this time adjust the threshold slider in DSS until it only detects 100/150 stars. If its picking up and registering noise as stars it wont remove them.

I thought the AR coating was supposed to face towards the scope. The unmounted Baaders have an arrow penciled on the edge to indicate which way to orientate them. Baader recommend trying them facing the opposite way, ie, toward the camera to see if it makes a difference. I'm not sure which side the mounted filters have it applied. The ZWO filterwheel has a female M42 thread both sides so can face either way. I currently have AR coatings facing the camera, ie, penciled arrow facing the camera.