smr

Hi, 

I'd like to buy an OAG but have no idea as to what to get. I've only just started reading up on OAG so I'm very new to this. 

Thanks for any advice.

I was a bit worried when I first got my L-eNhance Filter, in that I couldn't see diffraction spikes with my bahitnov mask in live view mode, but you just get around this by taking an image, say 5 seconds, and then checking focus, if it's a little out, adjust focus slightly one way or the other, take another image, and see how far out you are and adjust accordingly repeating the same process. 

Doesn't take me long to focus now I've got into the habit of it, although I'll be buying an electronic focuser soon anyway.

1 hour ago, teoria_del_big_bang said:

If you are only getting the LRGB filters why not go for the colour version of this camera it has had some fantastic reviews, or are you hoping to go NB later on ?
The colour camera will keep another 800g or so weight off the focuser.

Steve 

Thanks for the replies Steve. If I went for Mono and LRGB it'd be a fairly considerable improvement in Signal to noise compared to the Colour Camera wouldn't it though, and yes if I went for Mono I'd have the ability to do proper narrowband imaging later on, after I've learnt how to do Mono imaging and focusing etc.

Re the stock focuser - I'll be upgrading to the ZWO EAF anyway as soon as they're back in stock so that would cover any issue with that wouldn't it? I'd definitely want to add automated focusing regardless of whether I go for OSC or Mono.

I'm am undecided though as to whether to go for the OSC or Mono but just trying to establish what I would need if I went for Mono.

Thinking of buying the QHY268M and taking a quantum leap upgrade

I'd go for the QHYCFW3-M-US (7 X 36MM) Filter Wheel

This works out at £2k, which is my budget, and doing so I may as well spend a few hundred quid more and buy some filters as well.

What is the difference between the Baader LRGB and LRGBC Filter set and which one would I need to go for ?

Also what's the difference between the Baader and Astronomik LRGB set, both sets are around the same price...

Or... can anyone recommend a good set of LRGB filters? I can't afford more than £500 so Chroma and Astrodon aren't viable options, and the cheaper the better but not cheap cheap, so around £350ish would be good.

And last but not least will all of this work with my Z73 Refractor ? 

I'll buy a ZWO EAF when they're back in stock so I can automate focusing.

Astronomik https://www.firstlightoptics.com/rgb-filters-filter-sets/astronomik-deep-sky-rgb-filters.html

Baader https://www.firstlightoptics.com/rgb-filters-filter-sets/baader-lrgbc-ccd-filter-set.html

27 minutes ago, vlaiv said:

Interestingly enough, there is single small change that sensor manufacturers can do that will negate difference between OSC and mono.

Don't know why they don't already do it - I think it would improve daytime photography as well (color rendition and low light performance).

Instead of having RGGB as bayer matrix - we could have RLGB - one of four pixels could be without filter.

That's a good point, I wonder why they don't. 

Just now, teoria_del_big_bang said:

Can you share it ?

Steve

https://www.cloudynights.com/topic/753265-received-my-qhy268m/page-3

I've just seen a 10 minute sub of the Rosette Nebula with the QHY268M, from Bortle 9, which packs more detail than 6 hours integration with my DSLR in a Bortle 5. 

😮

I have been dithering over a dedicated cooled Mono or dedicated OSC for some time now. I feel like I have read and watched thousands of articles / videos comparing the benefits of both as well as studying astrophotography images and asking lots of questions on the topic. I've never had a harder decision to make when it comes to buying something for a hobby I have.

Overall when you see the images of LRGB and Narrowband they are better resolution with much more detail than a typical gallery of OSC images, and I do love pure narrowband images. The stars also appear smaller in Mono images.

Just when I'm leaning towards Mono+EFW+Filters I'll see spectacular data and images from imagers with OSCs, for example the work @Allinthehead has done with his OSCs, and most notably of all, for me, the Horsehead and Flame Nebula image which is a result of the 2600MC Pro (OSC) and Tak 160 combination, although in favourable skies and with a skilled imager it has to be said. But, it shows what can be done with the kit. That kit isn't cheap though, both items will cost a total of around £5k.

It's perhaps not a fair comparison, in that I've surely not seen every Horsehead image there is, but it's the best image of this DSO that I have seen thus far and it happens to be OSC. I'm not biased one way or another at all.

I'm so close to buying my first dedicated astronomy camera and basically it's a choice between Cameras of the same sensor, the 2600MC or 2600MM (or the QHY version). Cost doesn't really factor into it for me because if I went for Mono I'd be happy enough taking Mono images to begin with, and it wouldn't be too long before I'd buy the EFW and Filters, I can't afford to buy all in one go.

It's just weighing all this up, do I go for an OSC and then when I can afford to buy a fast scope like the RASA f/2 or a Takahashi, or do I go for Mono+EFW+Filters and image with my current scope at f/5.9

I could always upgrade to a faster scope a year or so later.

I'm an IT and Computer Engineer so I don't mind the computer work and technical challenges, in fact I enjoy it, so I would probably enjoy Mono in the sense that it's more technical than OSC / more things to get working together to achieve an image. Having said that there's also another good reason for going for OSCs though - fast lenses. 

Using the Canon 200mm 2.8 or Samyang 135mm 2.8 with a 2600MC Pro would be superb I think for those really nice wide widefield images.

I do feel a little put off by some comments I've read by imagers who seem quite annoyed at the clouds and weather patterns we have here in the UK - when trying to image a target and having the data collected for L,R,G but then not being able to complete B before the target has moved into an obstructed position after a consecutive run of cloudy nights, and it's a matter of waiting another year for the target to come around.

Like I said, difficult decision. 

I have an l enhance filter which I use with my 600D. Good combo which I am happy with.

1 minute ago, SamAndrew said:

Depends on the F ratio of you telescope; faster scopes may need bigger filters, so I'd go up a size to cover yourself for future upgrades. Ideally a 7 position wheel for LRGB HA SII OIII. 

As already said, you'll want to add an autofocuser, as you don't want to be slewing back and forth and having to recenter the image between filter changes. You'll also need to shoot flats for each filter to correct for dust on the individual filters. 

Thanks. If I was shooting one filter a night, say just L for one night, I'd take flats at the end of the night. 

But if for whatever reason I wanted to shoot G and B the second night, do I take flats after G and then again after B or can you take flats for both filters at the end of the night?

32 minutes ago, Starflyer said:

When I swapped from a DSLR to mono the first thing I learnt was that parfocal filters aren't and I absolutely needed to refocus on every filter change. This soon became a real chore and I added autofocus, it's one of the best additions you can make.

I started off with SGP refocusing on every filter change, and as this takes time I'd run all my blue subs, then green then red.  I found this was resulting in too many partially completed images, so I worked out the focus position offsets, initial focus is done with L and I can now run B - G - R - L subs and know the focus will be spot on for each filter.

Another advantage of autofocusing is staying in focus as the ambient temperature drops.  I autofocus every 1.5C temp change knowing I'll always have spot on focus.

Your example workflow assumes you'll have a four hour window of clear sky, the recent weather proves this isn't always the case.  You can of course shoot over multiple nights and I almost always do this, but with autofocus you can have subs to create a usable image after a relatively short period of time.

 

Thanks yes i would definitely add an autofocuser. I will buy the ZWO EAF when theyre in stock. 

I dont mind imaging over several nights. Infact this is my usual routine with my DSLR. I usually like to image a target as much as I can so I would typically spend several nights doing so.

So if we had 4 clear nights a month, I could image L one night, B the next, then R then G. Hopefully 4 clear nights a month before whichever DSO I'm imaging is unobstructed.

Do you have to work out focus position offsets with an autofocuser? Not sure what that means.

On 27/01/2021 at 13:17, teoria_del_big_bang said:

Are you wanting a video about the imaging side (i.e taking subs, darks, flats etc) or the processing side (alignment,stacking,stretching etc) ?
In my opinion whilst there is a lot of very good info on you tube and the like if you want an overall summary then I think you are better off with a book. If you don't have it get "Every Photon Counts", its a  must, as useful as the camera, scope and mount in my opinion. 
It may not go into every aspect in depth but really gives an overall view of what is needed both imaging and processing.

I am not sure exactly what you are after I know you are not totally new to astronomy so is it just the mono side of imaging (i.e. needing multiple filter subs) that you are unfamiliar with ?

Depends to an extent on your setup (which scope, camera and distance from camera to filters and this tool will tell you exactly.

CCD Filter Size Tool

But I looked at a few scenarios with scopes and cameras and generally seems that some MAY get away with 31mm bu generally 36 mm unmounted seem to be the safe minimum.

Steve

It says minimum recommended filter size 30.34. So would 31mm filters be ok?

With regard to Mono imaging...

Just so I'm on the right track with how a Mono imaging session would go ... if any of it's wrong please let me know...

If I were to buy a Mono APS-C and a Filter Wheel, and I went for just LRGB Filters. I would need to buy

Camera
Electronic Filter Wheel, 5 or 7
LRGB Filters 

If I had a 4 hour imaging window for example.. I'd have everything ready to go and start off by just shooting an hour of L, the software then automatically switches the filter wheel around to the Blue Filter, I have to refocus by slewing to a bright star, put on bahitnov mask and focus, slew back to target and carry on imaging, then after another hour I repeat the same process with R and then G, at the end of the 4 hours I then take flats with the G filter in place for all filters. Imaging session complete.

This is really exactly what I'd like to know - how that is done ^ because at the moment it's very basic with my DSLR, just focus, slew to target, plate solve. Shoot, take flats at theend of the session. Just want to be sure what is different and what is involved with Mono imaging.

Really appreciate any help!

2 hours ago, nfotis said:

At least, Astromechanics has an ascom compatible focuser for EF lenses.

Another possibility is to use a follow focus ring and handle.

N.F.

Thanks. Hadn't heard of that before. Looks like it would work great. Would it be able to autofocus for temperature drops. ie. connect it up and leave an imaging session running for 6 hours unattended? 

I suppose if that covers the focusing and autofocus solution it just leaves the question as to whether the lens is optically sound for astro. 

I know it is for terrestrial photography. It's probably the sharpest Lens Canon have ever made.

The reason I am wondering about the suitability for AP is because I have been thinking about buying this Lens for wildlife, landscape and sport quite a lot over the past year but didn't get around to it.

If the lens is suitable for AP it could be worthwhile investing in as I could also buy a 2X Extender and then get 420mm at f/4.

Hi,

Just wondering if anyone has one of these Lenses for Astrophotography. Apparantly the mk1 version isn't very good for AP according to Jerry Rodriguez and his tests with it.

I can't find much info on the mk2 Lens though. At such an extreme focal length and aperture combo I've heard that focus is more difficult... is it possible to use an electronic focuser with these big prime lenses ?

1 hour ago, bottletopburly said:

Deepskydad af3 focuser will work Pavle will confirm if you email him 

https://deepskydad.com/autofocuser3

Better than the ZWO EAF ? Just realised that would work with my scope but no stock anywhere at the moment.

Hi,

Just wondering if anyone can advise as to a good autofocuser for William Optics scopes, particularly the Z73.

One word. APOD. Actually thats 4 but still....

Hi,

I'm thinking of buying the ZWO 2600MC Pro with the Zenithstar 73 0.8 Focal Reducer.

If my Maths is correct this should provide a 344mm focal length (430mm x 0.8) and an f ratio of 4.72. Is this much faster in terms of light gathering than 5.9? 

The actual fov isn't drastically different. If I took images with the focal reducer and then cropped in to the 430mm focal length fov of the scope, would there be the same sort of detail being that more light has been gathered ?

I wouldn't want to crop in all the time anyway, there are plenty of targets which would benefit from a wider fov such as the Witches Head which would be framed more nicely etc.

Also would there be any other things to think about when imaging with the focal reducer and this Camera? Would there be any vignetting ?

Here's the fov at 430mm

And with the 0.8 reducer at 344mm

12 minutes ago, Starflyer said:

I've been hovering over the buy button on the QHY but I think I'll hold off until the summer.

For me it'll mean a new filterwheel, filters and OAG, so the early bird discount isn't as important as getting it right first time.

I may well end up buying ZWO, by holding off for a while I get the benefit of seeing what problems each brand's camera has after launch, if any.

I haven't owned a serious camera from either brand, but my gut feel is saying go with QHY. If Atik launched a camera with the same sensor then that's where my money would go.  This hobby is difficult enough at the best of times and reliability means everything to me.

That's fair enough and quite sensible. Although saying that, I don't think there will be much to choose between both Cameras if they are anything like their OSC models, I'm not sure how the design and manufacturing differs between Mono and OSC though so we'll have to see what they're like when people really begin to start imaging with them. 

5 hours ago, tooth_dr said:

I have a QHY268M ordered, should be here next week.  The decision was influenced by availability and by cost, and by reputation of both vendor (MA) and QHY.  I already own QHY cameras so I trust the brand.  If the ZWO had been available when I ordered the QHY and was the same price as the QHY then I may would have chosen the ZWO.  However I dont like to invest too much in one brand, and prefer to have a variety of cameras, scopes etc.  I recently bought a ZWO2600MC, and was specifically after a matching mono camera for a dual rig.

 

Is that to combine luminance from the mono with rgb from the osc or will you be using an efw and filters with the mono?

Just asking as this is something I've been thinking about, it'd be great to have two scopes the same and a mono and osc camera of this sensor.

45 minutes ago, teoria_del_big_bang said:

Are you wanting a video about the imaging side (i.e taking subs, darks, flats etc) or the processing side (alignment,stacking,stretching etc) ?
In my opinion whilst there is a lot of very good info on you tube and the like if you want an overall summary then I think you are better off with a book. If you don't have it get "Every Photon Counts", its a  must, as useful as the camera, scope and mount in my opinion. 
It may not go into every aspect in depth but really gives an overall view of what is needed both imaging and processing.

I am not sure exactly what you are after I know you are not totally new to astronomy so is it just the mono side of imaging (i.e. needing multiple filter subs) that you are unfamiliar with ?

Depends to an extent on your setup (which scope, camera and distance from camera to filters and this tool will tell you exactly.

CCD Filter Size Tool

But I looked at a few scenarios with scopes and cameras and generally seems that some MAY get away with 31mm bu generally 36 mm unmounted seem to be the safe minimum.

Steve

Thanks Steve, not the image processing side of mono for now but rather a guide on how it works with regard to image capture. Would be nice if there was an in the field walkthrough on youtube of someone doing this but I can't find anything similar to that at all, kind of surprising to me given the vast amount of astro videos on there. 

Maybe there isn't because I'm just overthinking things and imagining it's more complicated than it is.

It'd just be nice to see someone showing the process I guess, with an electronic filter wheel and the process of how it's all connected up, taking flats, imaging, how the filter wheel and imaging plan works between hardware and software etc.

Does anyone happen to know of a video which demonstrates all the steps involved in Mono Astrophotography? I've had a search on youtube but can't seem to find any sort of walkthrough or clear guide as to what is involved from start to finish.

I'd really appreciate a video like this!

Also with regard to the APS-C Mono Cameras, what size filters would you need ?

Imaged over two nights.

Canon 600D, Optolong l-eNhance Filter

5 hours 26 minutes, 233 Subs, 20 Flats, 200 Bias

Just when I'm so close to buying an OSC and then you come up with this from a Mono Camera in Bortle 7. That's just stunning! Lovely image.

Excellent first light. Already showing a lot of dust with just two hours integration time. So f 4.4 then?