gilesco

Go for it, works really well, I bought two as thought it might split or I might mess it up, if your tube rings have the same holes top and bottom then use the existing plate as a template. Much lighter than a metal plate.

A perspex sheet and some 1/4" screws

Yes, just remember that the Pi4 needs 3A + of power, best suited with another powered USB hub, which you can find ones that run off 12V sources. I only say that as the PowerTanks have USB, but I'm sure you already are aware, they only supply 1.5A or 2.1A at best.

Set up just before imaging on 24th December:

I used one of these in a Cigarette Lighter socket: https://www.amazon.co.uk/gp/product/B07L2YWVLC/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 I now use the port 1 on the Pegasus PowerBox Advance, which serves other purposes too.

One way of improving the performance of the Pi is to use a SSD instead of the SD card, a nice case that uses a SSD seamlessly is the Argon One M.2 case, I have blogged about it on my website.

Yes, I have both of these, together with a ASI1600MM Pro, OAG etc... They all work with INDI pretty seemlessly.

Astroberry is based on Raspbian, which is 32-bit currently. Now, there is a 64-bit Raspbian in the works, but Astroberry is based on the 32-bit version currently. Under Linux, when running on a 32-bit operating system any one process can only address 4GB of memory. So the only benefit of 8GB, at the moment, is that a number of processes could simultaneously use more than 4GB between them, but individually they would only see a 4GB address space. Now things may change in the future, and you might want to look at your usage, if FITS viewer and Ekos and Kstars are different processes then there is some mild benefit there as you might have some extra headroom. But by and large, the only benefit of the 8GB version is you might future-proof yourself by going for the higher spec. Raspberry Pi Foundation seem to come out with a new model and revision of the Pi quite often (perhaps at least once every two years), and personally, I just can't help buying the latest and greatest whenever a new one is released.

The moon is often overlooked, but is actually a spectacular object to try higher magnifications on, you see so much detail that you sometimes want to just reach out and touch it!

Also, just because you have a barlow, doesn't mean you have to use it. start without it, as mentioned with the 20mm, and go to the 12.5mm once you have something in view, if you feel you can still go further try the 20mm with the 3x barlow, which will be a magnification in between the 12.5mm and the 4mm. You'd need excellent conditions, pretty good eyes and focus ability to use anything with more magnification.

You can even switch the Telescope Simulator to use your mount indoors, and just add the CCD Simulator. A kind of fun way to play if the weather isn't good, the frames that the CCD Simulator gets from the GSC are hardly awe-inspiring, but they will be a valid star-field.

If you have GSC (Guide Star Catalog) installed, then you can just fire up Ekos with a Telescope Simulator and a CCD Simulator, take a sub-exposure with the CCD Simulator and Plate Solve that!

From what I have heard, the EC models don't really pay for themselves in a performance sense until moving to the 50lbs+ range.

I see the iOptron mounts (26 / 28lbs load items) now on the website, these didn't get quite the fanfare I was expecting. The 25 is still popular on the secondhand market (not usually on the market for more than a couple of days before sold).

I amazed how quietly this has become available... Would have expected a bit more of a fanfare...

So this is the only image I have made with the Esprit 120. I am happy with it, it is my first image with it, I am not complaining about it, there is a lot in there that is an imperfection of my own processing etc... I only started this thread with a concern about having the "in-focus" position at an outer point in the total focuser walk.

The initial result I've got from the 120 tell me that backfocus is just spot on with the FLO supplied adapter for CMOS cameras. I had heard about the manual errors, back focus worries before purchase etc ... but FLO supplied everything to make it work! No extra stuff needed, will probably post an instance of my first image, from a single bad seeing session shortly.

Can't help but notice you have a Pegasus attached there, how did you go about that? (I'm choosing to mount it on something attached to the tube rings).

Beautiful set up by the way. I think it is by design, to just allow for extra non-focus stuff after the tube. Any fears I had are alleviated, just initial quandries.. "why did they do it that way", "why is that like that", etc...

After spending years taking a vague interest in Astronomy with just Binoculars my wife bought me a telescope, and she bought me the Celestron branded of exactly one of those. It started me off, I managed to get lovely views of the moon, and managed to focus on the planets a couple of times. We also used it to spy wildlife in the fields out the back of the house, so I would think it is OK for someone who might generate an interest in Astronomy, and has a general Interest - wildlife, birdwatching etc... I've now moved on, but it is still an easy scope and tripod to just get out the back and point at the moon - whereas the rest of my kit does take about 30minutes to set up (it's an imaging rig). However, since then, if my wife wants to buy me something then I ask her to contribute to my budget rather than surprise me with something. I think she sees now how my hobby has grown and wouldn't be able to make a decision on my behalf as to what I might want to buy next. A word of warning on these, the spotting scope eyepieces are rather non-standard if you are trying to fit astronomy eyepieces, they're not 1.25" nor are they 2". The Baader MkIV Zoom lens does however come with adapters that allow fitting to a spotting scope.

I am not trying to change how far back my sensor is. Perhaps this (it is an exaggerated scale) will make it more clear. When the tube is extended further there is more sag (upper image of focuser tube and draw tube): If the tube achieves focus without being as extended as much (lower image) there is less sag. Of course the lower image means the camera is closer, and so spacers are required to the right of the drawtube to compensate for that distance. In any case, as others have noted- and this is an exaggerated scale, the Esprit focuser is a very snug fit and others don't expect this issue. But if you had a cheaper not so snug focuser, it would be an issue.

Of course, the upside of this is you have space to add extra gizmos (e.g. a flip mirror) in the train and you will still be able to focus, whereas if the focus was just 25% tube extracted then it limits the number of gizmos that you can attach and not be able to focus at all... I'm going to stop worrying about this now 🙂

Thanks @Laurin Dave if the Esprit 150 is similarly in focus with the drawtube quite far out then I'm guessing it is normal. It feels like a good sturdy well built focuser without any "give", but as I am new to the Esprit I wanted to satisfy that what I was seeing was normal. I'll continue as is, but if I see a 20mm - 40mm M74 or M65 spacer at a good price I might just bite for it.

Yes, on page 11 of the Esprit manual https://inter-static.skywatcher.com/upfiles/en_download_caty01416868621.pdf I'd look for a spacer between either: Focuser Tube and the DrawTube Adapter M74 male to female DrawTube Adapter and the Field Flattener M65 male to female I actually already have a 9mm AstroEssentials Filter Cell adapter connected between the DrawTube Adapter and the Field Flattener, fitted with a 2" IDAS Light Pollution filter.