The Admiral

True, they have their drawbacks, but the lack of an anti-aliasing filter and good Ha response has given me some pleasing images. I had my X-T1 available anyway, so why buy something else? I wouldn't necessarily buy one if I had nothing else to use, but good enough for what I need at the moment, and would only be replaced by a proper astro camera. Ian

Ah, sorry, I didn't read the thread carefully enough. Ian

You could also look at http://astronomy.tools/calculators/guidescope_suitability on the FLO website under astronomy.tools Ian

Well of course I specifically asked in relation to my GEM45. One would expect that the CEM40 would also have that feature if there is the same command in the handset. Ian

Title says it all really. Just a heads-up for users of Fuji cameras with the X-Trans sensor or SuperCCD, Astro Pixel Processor release 1.080-Beta 2 is now available to download. https://www.astropixelprocessor.com/community/release-information/astro-pixel-processor-1-080-preparing-next-release/ Ian

I emailed tech support at iOptron today, asking what each command does. I received this speedy response: "Set zero position: This command set the current position as zero position. It should be executed only if the mount is at true zero position. Usually after a star alignment, and goto zero position. GoTo zero position: This command should slew the mount to the memorized zero position, or the zero position with newly correction by star alignment. It is useful to check whether zero position is altered in case the motor skipped step (grinding sound). Search zero position: instead of set the mount at zero position physically, i.e. the telescope point to the Polaris (north), the counterweight shaft point to the ground, one may use the search zero position command to move the mount to zero position physically. The mount has imbedded sensors to find zero position." I'm not sure that that is entirely clear either. Interesting though that the mount has embedded sensors to find the zero position, I didn't know that before! As Fegato says, but why it isn't obvious from the manual I don't know (unless I've missed it!) Ian

I suppose the question that comes to mind is whether it is seeking its 'native zero position' (if such a thing exists), or whether it is returning to the last saved zero position, though I would think that would happen with the command 'goto zero position'. I'll try the search command next time when I eventually get around to using the mount again. Ian

Indeed! Ian

Thanks for the input, but would I be correct in assuming that you are using a permanent set up, where you can switch off, leave the mount, and then come back and switch on again? When you have to set up and tear down for each session, you end up unlocking the axes after the mount is put back in its case for transport. So re-setting the zero position sounds like the correct thing to do. Ian

Thanks very much for your input and link Anne. Me too, but I don't have a camera which has an accessible image (it's a mirrorless camera), so I can't plate solve. I have taken to doing a 3-star align before slewing to my chosen target. This part of #9 of the link, is basically what I do. "2) Level the tripod, point counterweights down and DEC veritcal using a level if you wish. The enter ""set zero to current position". This will now be the new zero position." It has a level but only on the base of the mount. Hmm, interesting routine you do. Ian

Anyone? Ian

I'm a little unsure about setting up my new GEM45, and would appreciate some advice please. I would suspect that the setting up procedure is common to all the later iOptron mounts. I set up and tear down for each session so I normally 'clear alignment data' before doing an alignment. I'm assuming that the stored alignment data is no longer pertinent to each new set up. Is this correct? Before I perform an alignment I align the mount to the 'zero position' by eye, and then use the 'set zero position' command on the hand controller. Is this correct? What are the commands 'search zero position' and 'goto zero position' used for then? Does 'search zero position' make the mount find its own zero position? None of these things are explained in detail in the manual (so far as I can see), so any help would be appreciated. Ian

Does DSS process the Fuji XT3 raws or did you convert to dng, tiff or jpg first? Ian

That's a great first image and it shows how well the Fuji's detect the Ha. What did you use to stack them with, as a matter of interest? I think the star elongation might be due to coma rather than polar alignment as the elongation appears more radial than in one direction. Ian

I can't see any information about the passband widths, even on the Optolong website. Any idea of what they might be? Ian

I use the iPolar as it came with the mount. I've never done a visual polar alignment, but I wouldn't want to be craning my head to look through the scope. The iPolar is dead easy to use, just align a cross within a circle. I haven't used it enough yet to see how good alignment is. Also, using a DSLR which is not Canon or Nikon, and not yet guiding, does mean I don't have an image readily available for plate solving. Ian

I don't have any problem on that score. Ian

I don't think so as the washers are the same diameter as the head. I think their purpose must be to allow some slippage so that the mount can be adjusted for Az against the pin. I'm not quite sure I follow, but using the Allen key of itself isn't really a problem, it's just that for operations which have to be repeated each time the rig is set up it would be less fidly and more convenient if they could be tightened by hand. You always run the risk of dropping the Allen key in the garden too! All the more so as in order to put the mount back in its case they have to be slackened off again so as to allow the altitude setting to be reduced to ~40°. Note that these bolts have a shaped shank, they are not straight bolts. You are right about minor flaws though, if they can be called flaws. Perhaps I am just being picky. But thanks for the suggestions anyway. Ian

I'm sorry but I can't help thinking that you are over thinking the issue of long exposures on a DSLR. It strikes me that you will have more pressing issues to work through, not least the issue of selecting a suitable mount and guiding. Also, if you are keen to avoid wasting your efforts by trying to get the kit you need first off, rather than by building up as you gain experience, then perhaps you ought to be considering a full-frame cooled mono camera, LRGB filters, and a mount in the Mesu or 10Micro league. Sorry, I don't mean to be disparaging, but I think you will likely end up disappointed. Ian

Are you going to get away with exposures of greater than 30s with that set up? Ian

I think you'll find that Canon is supported, I know the link I sent was for Sony but you just need to search for the Canon version. See https://www.amazon.co.uk/Pixel-Wireless-Shutter-Release-Control/dp/B07M8J24NN/ref=sr_1_2_sspa?crid=3BDEGYTC887GU&dchild=1&keywords=wireless%2Bshutter%2Brelease%2Bcanon&qid=1588314232&s=electronics&sprefix=wireless%2Bshutter%2Brelease%2B%2Celectronics%2C205&sr=1-2-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExRk4xRUJZRTlENTUwJmVuY3J5cHRlZElkPUEwNDQzMzU4MUVaTVhUTlNQOTRUUSZlbmNyeXB0ZWRBZElkPUEwNDIyMjY2NVpTUkdNMFRKSkhRJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1 It just comes with a different inter-connecting wire. There are many "brands" that do the same thing, but a lot are just re-brands of the Chinese original! I did use a fully wired version but found it was getting a bit tangled in the dark with the handset lead, so thought I'd try the wireless version. Ian

Not the Canon but I have a Fuji X_T1 and that has a built in intervalometer but it only goes up to 30 second exposures. May be other cameras have longer exposures possible. This was OK when I used to do Alt-Az imaging, but since acquiring an EQ mount I want to take longer subs. I've just got one of these. It sits in the flash mount and a short cable goes to the camera remote release socket. It is controlled by a remote handset which communicates via wi-fi with the shutter release. So if all else fails, you could go down this route. They can be bought for use with different cameras, just the interconnecting lead is changed. Ian

Glad my redundant StarSense is working out for you ☺ Ian

Link sent.

Thanks. I'm on my laptop at the moment and I realize that I will have to start up my PC to get to the FITS. Will do that when I'm next on it if that's OK. But it also means that I must have used the earlier version of ST; the latest version should give better results anyway. Cheers, Ian