Avocette

Prompted by a post elsewhere, this question is on the pros and cons of placing multi-narrowband filters in front of the FR/FF or between it and the camera. In both my systems (ED80 and 61EDPH II) the initially convenient place to put 2” mounted filters is in front of the FR/FF where they can screw in without affecting the FF to camera back-focus distance. However, changing filters is tedious and risks finger marks or worse, so I have been contemplating buying a ZWO slide-in filter drawer and some extra filter holders which would replace the ZWO 20mm spacer in front of the camera. My concern with making the change, apart from the difficulties of getting hold of the hardware, was whether this might mess up back-focus. This advice from Altairastro leaves me confused…https://www.altairastro.help/info-instructions/faq/can-filters-be-placed-in-front-of-a-focal-reducer-flattener/

You’ve touched on an interesting issue here! Maybe ‘Getting started in Imaging’ would be a better place to ask the question?

Noctilucent clouds with a small amount of Cumulus over the Jura - 25/6/2021 20:14:43 UTC - Canon G7X II at 8.8mm (35mm equivalent of 24.6mm) focal length, ISO125, 1 sec at f1.8 (handheld!)

Noctilucent clouds framed with Linden tree - 25/6/2021 20:12:54 UTC - Canon G7X II at 8.8mm (35mm equivalent of 24.6mm) focal length, ISO125, 1 sec at f1.8 (handheld!)

Noctilucent clouds framed with Cassiopeia - 25/6/2021 20:27:44 UTC - Canon G7X II at 8.8mm (35mm equivalent of 24.6mm) focal length, ISO6400, 1/10 sec at f1.8

Hot news from @RadekK - he has just updated the repository: “New version of KStars and INDI in da House! 🥳🥰⭐️🚀 Updated core components: - KStars 3.5.3 - INDI 1.9.0 - PHD 2.5.9 (dev5) - Oacapture 1.8.0 - all INDI drivers and libraries. Upgrade and enjoy!”

From your signature it seems you put your money in the HEQ5 mount. I think that’s wise, but with a small refractor, your EQ5 would have done OK providing you autoguided and would have let you image larger targets without having to make mosaics.

Take a look at the thread from @Captain Magenta about reverse engineering his Maksutov-Cassegrain (SkyMax 180).

You need to check on YouTube. The author of the channel called Jenham’s Astro does a lot of imaging with Maksutovs including the SkyMax 127.

I bought the ASI533MC a year ago and spent a lot of lockdown capturing loads of DSOs with the SW ED80 that are remarkably well framed in the square format. It actually also simplifies the orientation of the camera - no issue with rotating landscape to portrait and back again. I really appreciated the images I obtained after about an hour per target (at -15° and gain 100 - effectively unity gain). My earlier camera was an astromodified EOS550D and the improvement especially in summer temperatures was staggering. I tackled some mosaic captures for larger DSOs which worked remarkably well, but being conscious of the limitations of clear sky time, and my advancing age I suppose I might be missing out on sensor area for some wider area targets. However the 533 and ED80 is a great combination for many, many DSO targets.

I started my astrophotography journey a couple of years ago with a DSLR and a Raspberry Pi 4 running KStars/Ekos/Indi although not in the Astroberry package at that time. The DSLR images were large and image downloading took a bit of time, so the iterative PA process was noisy (shutter clicking) and not swift, but I was still very pleased to have the option. My AZ/EQ5 mount doesn’t include a polar scope, and my back didn’t enjoy the contortions I used to go through to polar align my earlier EQ5 Synscan mount. In those days SharpCap Pro didn’t allow PA using a DSLR, but I think the latest SharpCap Pro beta 4.0 may have added DSLRs into the camera list. These days I use an Astro camera with a smaller sensor, hence faster update and download, and no clunking shutter. ’just noticed that you’ve also got an ASI120MC-S. I have one which works very well for the polar alignment and also for auto guiding in Ekos.

More explanation please!

It just seems a bit sad to not take better advantage of the area of the flat field of the Petzval Redcat.

If you would like to play some other number calculations, what about the ASI294MM-Pro with its hardware un-binning? Sorry - ZWO call it Unlocked Bin 1. From the FLO website: Unlocked Bin1: 12bit ADC, 2.3um pixel size, 47 megapixels, 8288*5644 resolution, 14k full well capacity. Bin2 (The default mode): 14bit ADC, 4.6um pixel size, 11.7 megapixels, 4144*2822 resolution, 66k full well capacity. [by the way did you mean ASI2600MM-P rather than 6200?]

@Grumpy MartianI think I'm right in thinking that you used to have a SkyMax 150 Pro for planets and the moon? - how did you get on with it? I have seen a YT video which compares the SW Mak 127 versus Max 102 where the 127 certainly won.

Have a look here -

Well, there’s a growing happy band of Raspberry Pi/ Astroberry Server users you could join. You need a RPi4, with 2GB will do but 4GB is better, a 5V power supply, and a 32GB microSD card with a free download of the Astroberry bundle. There’s a FaceBook group and plenty of information on websites and forums. Perhaps start with www.astroberry.io for information about the software package, and the PiHut etc for the hardware. All is controlled by WiFi from the Astroberry hotspot so you can be nearby at the beginning to do your polar alignment and set the image capture controls, and then go indoors and monitor (and control) from the warmth. If the WiFi link fails for some reason, the RPi carries on doing its jobs independently.

Another very interesting post - thanks for pointing me to it! I suppose I am relatively lucky with my light pollution then, since it is yellow streetlamps which shine on my telescope. However there are four of them, all in the S to SW direction, so for any targets which I need to image near the Meridian, we’re in LP trouble. The attached photo shows the Moon,Jupiter and Saturn a couple of days before conjunction......

Interesting experiment - thanks for making the results nicely accessible! Did you use any filter during image capture?

The AZGTi wasn’t called the AZ/EQGTi when it was launched in 2018! So the fact that already with a change of firmware and the addition of an equatorial wedge you can do some serious astrophotography suggests to me that the software situation is pretty much under control. Perhaps I should have added ‘now’ because there have been teething troubles over the years and if you want to use guiding an earlier firmware v3.20 is better than the latest published version v3.26. People seem to have experienced examples of mounts that work and some others that don’t although it’s not clear reading the forum threads what faults there have been. My personal experience is with the AZGTi on a SW wedge carrying a 61EDPH II and ZWO miniscope for guiding. I use a Raspberry Pi 4 loaded with Astroberry to control via WiFi from my laptop. I began by using the AZGTi wireless communication from the RPi hotspot but that constrained the RPi to use the 2.4GHz WiFi bands. So I now use an EQDirect cable and operate the RPi on 5GHz WiFi. I am a retired electronic engineer so I am much more comfortable with hardware than software, but there is no doubt that I have had to gain some software skills climbing the astrophotography learning curve. I would like to get to the bottom of the variability I find with my guiding error curves, but In the meantime I continue to have made some images that please.....

Don’t worry about the square sensor - as @DaveS says, it means you don’t have to keep rotating the camera through 90°. No astro cameras presently offer golden ratio sensors........ When you want to get multiple things in one frame, do it by making a mosaic. My only question after owning my 533 for most of a year is, now that the 2600 is out, should I buy the big brother and sell the 533 to help offset some of the cost?

I had a bit of aluminium box section handy so tapped an M10 thread at the bottom to fit my AZ4 tripod base, and used a UNC3/8-16 bolt at the top screwed into the AZGTi pillar.

As @Stuart1971 says there is significant logical history in that some people wished (and may still wish) to run KStars/Ekos locally on their Mac or Windows laptops, and use just the Indi Server functionality remotely at the mount/telescope/camera position. In time the ability and speed of Raspberry Pis has made running everything on the Pi, and linking in by VNC Viewer or Browser to control and monitor, a really worthwhile option, especially since a break in communications leaves your imaging running.

I'm finding it particularly helpful to point the scope at Mizar in the Plough/Great Bear, when I want to adjust focus. You get three stars of various 'sizes' and hence three diffraction patterns to judge focus by. Mizar (Magn +2.22) is already a double with a separation of a bit less than an arc second, but in the field of view you also have Alcor (Magn +4.00), another double, and in between HD 116798 (Magn +7.78). This makes the Bahtinov diffraction pattern interesting - and I find the best precision if I refer to the tiny diffraction spikes around HD 116798.

To catch enough photons from M81 you will need significantly more time. With your 150 SkyMax Pro with the DSLR mounted, the actual focal length probably measures around 1900mm and the actual (measured) mirror aperture is 140mm, so the focal ratio is f13.5 or so. That means you will need about four times more exposure than what you would with an SW ED80 with its matching focal reducer/field flattener (~f6.5 510/80). I spend no less than an hour on a target like M81 and typically two hours or more with my ED80 and ASI 533MC pro.