Quetzalcoatl72

I haven't done planets in a long time, I was using an asi120mc but that is now exclusively my guider so I need a new camera for planets, I heard they're cheaper than deep sky ones as the chips are smaller. The last great image I did is shown in my signature below, I did do mars when it was bright early this year but I want much better images. I have a 8" scope now which Is better than my previous c5. I haven't tested it on planets yet because there is non till later this year. Any Ideas on what I should go for? preferably a zwo and I would like a filter to improve the image quality if that's possible, budget 500, thanks.

Lots of hubble images posted here somehow, I live in bortle 8 and I gave up till after summer solstice there's just no point. One whole hour of darkness isn't enough and the weather forcasts keep lying. No Idea how the above are getting those images this time of year. I did take this 1st of June tho. It was my first time guiding, using a CCD attached to laptop and plate solving. I can't wait till i can use my new found ability's on darker times. First time 300 sec exposure too, always been used to 2-3 mins.

On 03/06/2021 at 11:39, Second Time Around said:

I've noticed the vixen style bar is on the mount side of the setup. I'm using a losmandy, the vixen is on the opposite side of me, maybe it doesn't make a difference?

3 hours ago, pete_81 said:

I did a simple one for testing setups and guiding before really getting into bigger scopes etc - use DSLR + guidescope, attached to dovetail by quick-release mounts, similar to those found on tripod...

 

I like that pier going over the finder, i've noticed your dovetail is placed upside down compared to mine, how so?

20 hours ago, PadrePeace said:

I’m going to take a wild shot at an IR source given that you had a ring even on your darks. It’s been really  hot these past few weeks. Could it be that your sensor is picking up a warm spot or structure within your optical train? I know this sounds whacky but given Vlad’s observations on the lack of IR coating on the sensor window is it likely that given the multiple mirrors in that RC this might be the IR source?

Might be worth adding as IR filter right in front of the sensor. 

How many filters can you actually add to the camera without the image getting weird? in what order would the ir filter go with my Optlong LP and reducer/or/barlow

13 minutes ago, vlaiv said:

I just checked ASI533 has just plain AR coated window - that means it is sensitive in IR part of the spectrum. DSLR is not.

This could mean that problem is related to focal reducer - but it might be that it is not. It could be simple IR leak that just started to show for a different reason. What has changed in your setup or environment recently?

I just put the lens cap over when doing darks, and a hoodie or something draped over the top. I do remember putting a cloth over the setup shown in that picture and that took away one of the light rings in the darks, but one remained that I didn't get rid of, I could give it another go later to locate the light. Maybe I can figure it out during the day? as I wont be setting up for while. There's been no change other than lighter nights, and this was the first time setting up the asi/focal reducer combo.

Heres a stacked image with my dslr and reducer, if it's a leak I would be from the asi533 however that's not the case without the reducer. Looks like I'm going to have to so some choice of elimination. Sadly AP is impossible atm, I get one hour of darkness for another month or 2. I do not use covers of any kind, can you give me an example?

3 minutes ago, Adam J said:

That is a reflection of some sort probably between the focal reducer and the filter. Could be a poorly applied AR coating on either component. How old is the reducer? 

I only just got it brand new from FLO a few months ago used once with my DSLR never had this problem

33 minutes ago, vlaiv said:

That looks like rather nasty reflection. I wonder if flat would deal with that (I doubt but worth a try).

Did you take flats?

No but I have a feeling if I used a Barlow lens I'd get the similar results. Reflections can't have been from an external source however, When I was taking darks the next day(not added to this image) I could see similar rings on my darks which is literally impossible right?

This is clearly a terrible image. Mainly because of the bad seeing being middle of june and only 10 5mmin stacked images processed in APP. But clearly the major issue is the blue ring. This is only present when using my 0.75x focal reducer on my RCT 8" F/8 OTA. What can I do to fix this problem? The reducer is useless for me at this present moment.

Below is my camera set up before it goes in the scope. in order left to right:

ASI533, M42-M48 Adapter ,T2-M48 16.5mm Extender, Astro Essentials 0.75x Reducer for StellaLyra / GSO Ritchey Chretien, Optlong CLS-CCD LP Filter

4 hours ago, Merlin66 said:

They are all dedicated solar scopes!

All fitted with SW focus motors so they can be operated from within the office.

1. Fitted with a DIY CaK filter, x2 barlow and the ASI 1600

2. Fitted with a double stacked SM60 Ha, with SW motor tilt adjust, x 2.25 Hyperion barlow and ASI 174

3. Fitted with a Baader Cool wedge for white light and an ASI 1600

I see that that scope is a vixen not SW, I bet the focuser is much better, the sw80 I'm using slides out when when you tighten the screw, I do all my focusing manually. How did you get H-a with that?

On 13/06/2021 at 22:59, Merlin66 said:

I use three ED80 ‘s for my solar imaging.!!!

The standard focuser is OK and with the addition of a belt driven SW motor to the 10:1 knob it’s even better.

 

What is the purpose of using 3? wouldnt buying a dedicated solar scope be cheaper instead?

Focus was fine, it's better when theres a large sun spot, only a small one, i got lucky

On 10/06/2021 at 13:15, Atreta said:

Exactly

looking forward to see your images.

Here's a quick snapshot, i tried to stack the images together but it became glitchy, not sure what happened but it least its debayered. I was also worried about focus because theres no sun spots to test it on and the ed80 focuser is rubbish!

6 hours ago, Gfamily said:

Ian Morison (ex Gresham Professor of Astronomy and Jodrell Bank) has an Astronomy Digest post about the similar A5000.

The A6000 is better as it's easier to disable automatic Noise Reduction, which you don't want to use on Astro photography.

I have the A5000, which works very well on my smaller scopes (its body is ⅓ the weight of my dSLR) 

http://www.ianmorison.com/the-sony-a5000-apsc-mirrorless-camera-an-astrophotography-bargain/

Thanks, but what about when used through a telescope using imaging software?

I accidentally bought the wrong wide angle lens for my canon, now I own a Sony lens. Feel like I should just buy a new camera, one that's mirrorless because I heard they're essential now for some reason. I heard Sony Alpha a6000 is the best budget camera. Any other recommendations would be great, budget £500 new or used. I paid 160 for this Samyang 14mm ED AS IF UMC f2.8 as new, I don't feel like selling it 😕 .

Will it be better than my current canon 600Da?

Will I need to mod this one?

Can I use it for both the Milkyway, landscapes and deep sky astro?
Thanks

5 hours ago, Atreta said:

Hi, i think you have to debayer your image.

i did a little search and looks like the asi533mc pro uses rggb for its  bayer matrix.  have a look at this topic on sharpcap's  forum teaching how to debayer::  https://forums.sharpcap.co.uk/viewtopic.php?t=254

hth

 

ah so its when processing the images not when capturing them, so i'm safe? i just need to debayer when finished

Using Sharpcap to record the sun ready for the eclipse as a first timer. I did a 3 minute avi clip, and a snapshot, both show that the image is 'pixelly' when you zoom in, like checkerboard patterns. I have included a picture and the Sharpcap settings file. I couldn't get Nina to get the right settings so i used this program instead. If anyone could help solve this problem before the eclipse that would be great Thanks, if not then i will know for next time whenever that may be.

Sun_00001.CameraSettings.txt

2 hours ago, vlaiv said:

Here is what M31 looks like with that lens at F/2

The lens would be always used at f/4 not f/2 at that magnification though, no? I can't compare to those great pictures. The only 2 I have is one taken at 70mm and with the ed80, both only had several frames stacked, I assume that 70mm has bloated stars. As they looked great to me at the time, a time before guiding, precise polar alignment, smoother mount, and filters. Can't wait to improve upon these in the near future, still unsure about where to go from. I could do mosaics but I still desire a lens/small aperture scope for taking images of the moon, sun(solar eclipse) and nature as a whole.

Andromeda.TIF andromeda_80.TIF

20 hours ago, vlaiv said:

I actually figured that out by measurement of really sharp lens, but I think you can figure it out from lens MTF.

Here is Samyang 135mm F/2 lens - generally accepted as very sharp lens for astrophotography.

You'll see that it has about 92-93% MTF at 30 lpmm. That is 33µm (1mm/30) pixel size and it will not be perfectly sharp.

MTF of ideal aperture looks like this:

X axis is sampling frequency and Y is contrast loss. This function is pretty much linear. That means that attenuation to 90% happens in first 10% of frequency (or lowest 10%). Since we want wavelength and wavelength is 1/frequency - 1/0.1 = 10. So sharpness falls to 90% at 10 times the size of max wavelength that aperture can support.

Say we want to compare that Samyang lens at F/2.8 (which people say is sharp) to ideal scope of same aperture. 135 / 2.8 = 48.2mm of aperture. At F/2.8 that corresponds to ideal pixel size of ~0.5µm for diffraction limited scope (critical sampling rate) - and x10 longer wavelength is 5µm.

Yet from above graph we see that 90% is already reached at 33µm - far sooner (with larger pixels) than it should happen for diffraction limited lens.

If you've ever read lens review - you'll notice that they mention F/8 to F/16 as being setting at which image starts to get softer due to effects of diffraction. Above calculation supports that - sharpness of the lens below about F/8 to F/16 is determined by lens itself and not by diffraction effects.

I couldn't work out how to add lenses to Stellarium to see the field of view because it asks for aperture, that detail is never mentioned when looking at camera lenses, looking at these details you've provided I worked out that the current lens I have my eye on has an aperture of 50mm and that's the Canon EF 70-200mm F/4 L IS USM, does that sound pretty sharp to you? Than lens combined with the asi533 has andromeda in the perfect frame. The lens also can be zoomed in and out if I were to get something larger in the field. Thoughts?

4 minutes ago, vlaiv said:

Best approach for variety of reasons is to take all panels every night.

Imagine you image two nights and in first instance take half of galaxy on first night and half of galaxy on second night. It also happens that first night seeing is good and stars are tight and transparency is good, but on second night seeing is poor and transparency is poor. You'll be left with image that shows distinction both in sharpness and in signal to noise ratio - split in two.

If you image both parts on first night and both parts on second night - odds are that you'll average out both seeing effects and transparency issues. Image won't be as sharp as first night or as blurred as second night (and same goes for SNR) - but it will be the same average on both halves.

Never recorded anything over multiple nights, since my setup is never permanent I'd have to keep the camera in at all times when bringing the scope in i guess, keeping the same rotation, though i guess that doesn't matter as the sensor is square

8 hours ago, vlaiv said:

It is a bit more complicated.

You need to create sequence of couple of tiles - as @iapa already said - capture software has features to help you create mosaics - you just say how you want to do it and they create sequence with coordinates and all. After that - stacking software should deal with stitching mosaics as well - at least I think APP does that for you.

I made couple of mosaics and I stitched those "by hand". That is a bit more involved, but it can still be done.

Other than taking more panels and stitching those after (and any binning involved if you want to image in same time as you would capture target with smaller scope) - it is pretty much the same as doing LRGB - there you also need to do multiple sets of subs in different filter - here you only reposition the scope between sets.

could i not take a pic of half the galaxy and the other half after? and doing it in one night would be best, could be different seeing on the next night might make it off looking on one side

13 minutes ago, vlaiv said:

Just a question, why do you need to do it in a single go?

You can always do mosaic.  APP (not sure if you managed to try it out and if you like it) - will stitch them for you if I'm not mistaken.

never crossed my mind but it does seems more complicated. the closest I can get is my ed80 with a reducer, but I am not sure what reducer will work, it's almost in frame with a x0.50. do you know of any reducers?

14 minutes ago, iapa said:

A 200mm canon lens should be capable of that fov.

Or the Evoguide 50, 242mm f2 guide scope has good reviews.

 

You could also try using http://astronomy.tools/calculators/field_of_view/ calculator selecting various OTA/lenses

a guide scope that doubles as a good quality optic scope wouldn't be a bad idea thanks, tho they don't usually fit 2" adaptors so i'd need a 1.25 lp filter 😕

I have a asi533 and I want to have large nebula(veil, north america, horsehead, eagle) and at least the whole of andromeda in frame with a budget of no more than £300, Can anyone recommend a telescope or canon lens with that budget thanks!