Demonperformer

Silly boy! Just because the camera end of my FF has a male M42 T thread, doesn't mean that they all are. Just seen that yours has a M48 thread, hence the adapter and the extra 10mm, so I agree with your figures. Still, the 54mm front-to-chip distance, with the 17mm back-to-chip distance, would be just right for my optimal 55-57mm distance ... NO! CanNOT afford it ... this month!

But if you remove the front bit of the camera that will reduce your 17.5 to 6.5 and so your total is 1.6mm too little - unless I am missing something?

As a short-term fix, I don't know if this will help, but I used to have the same problem with the power supply to the SE mount. I was reluctant to start sticking screwdrivers into the socket to push the pins apart, and found that, if I looped the cable slackly over mount and then applied a couple of (separated) pieces of electical tape to hold the cable in place, it worked fine. Why I think that worked was that the slack in the cable and being held firmly in that position with the tape, meant that any movement in the system did not get transmitted to the plug and start jiggling it about - at least that was my guess.

Gina, I am sure people will be impressed whichever you choose, but, as you ask for a preference, I would say, do (5) as (i) it will be good to see if the esprit will perform without guiding, and (ii) you say you are "rather keen" - that is always a good thing.

Yep, that's the problem I was having when I PM'd

I agree with you that AT is about as much use as a choclate teapot for PA, but I have found it to be MUCH better at slew-and-solve. I will say, however, that it seems to be an awful lot faster with a 'lens' if I use the 41xx files (TYC2) rather than the 42xx files. Last time I was out, first GOTO from start (with VERY rough home position - camera pointing vaguely forward, somwhere along the dovetail bar) was about 2½° out, but it got me to within 10" on one move. Considering the image size was about 12"/px, I thought that was probably good enough!

Now, does that mean I turn the focus knob towards ∞ or away from it ... ?

Yes, you get more backfocus. For extensive discussion:

Two purchases recently from 365 Astonomy: (1) The ever-popular ZWO ASI1600MM-cooled. I had been considering this ever since I started following Gina's progress with hers. It was on offer at 10% discount, so I decided to "jump". Despite saying "Available now from UK stock", it wasn't. An email to Zoltan produced a quick response, advising that this "only indicates that we now keep it in stock usually in the UK". For actual stock availability of their website you need to refer to the "traffic light button" (see image). OK, for £130 off, I'm not going to gripe too much about having to wait an extra few days. It arrived on Monday (8 days after it was ordered), well-packaged and secure. (2) An adapter ring, to enable me to use 1.25" filters in the 2" filter thread of the EOS-lens adapter for this camera (an item I found to be not-easily sourced in the UK). This arrived this morning and does precisely what it says on the tin - screws into the 2" filter thread and accepts a 1.25" filter. Less than a week from ordering to delivery. Not going to complain about that. All-in-all, a happy bunny, who now wants some clear skies so he can go out and play with his new toys. Thanks.

Don't know if this would be of any use. I have one and the main body is genuinely 9mm. The threads on either side make the total 13, but the extra 4, of course, doubles up on whatever you attach to it. The catch is that, if you still need a filter wheel, that is likely to take you over the distance you have available! There's nothing for it ... you are just going to have to design a combined FW/OAG that meets your exacting standards and get the 3D printer on the job. The only 'optical' bit (I think) would be the OAG prism - and as you have just bought an extra one that could be cannibalised ...

Yes, polemaster is brilliant - and I speak as someone who was faffing around for (literally) years with other ways and never getting anywhere near polar alignment. Can certainly do 5m subs with round stars (on an EQ6!) and was going to try and push it further the other night, but the cloud rolled in. I'm not sure I would recommend it as a mandatory purchase with an EQ mount (because of the price), but if anyone was having the least difficulty getting PA sorted, I would not hesitate to recommend (because it is so easy & accurate). I have tended to pretty much ignore the final stage (from when you press 'Monitor'). As you say, it tends to dance around a lot, and I have also found that the adjustments can be so small that I can do more damage than good by trying to make them (also I get confused with translating up/down on the screen with which bolt to tighten/loosen on the mount, so am likely to go the wrong way anyway!).

'Brain the size of a planet' you mean?

Good news, Gina ... USB2 hub is included [phew!]

It does pose a problem, doesn't it? I wonder if SX will make spare carousels available separately, which would mean you could have a broadband wheel and a narrowband wheel.

Even to my unpracticed eye, that looks incredibly good. Think I won't waste my money on the 2" filters after all, and will promote the 1.25">2" adapter from 'in the meantime' to 'permanent'.

Just wonder, Gina. Are you getting much in the way of vignetting with 1.25" filters and this camera on your original subs. The fact that the EOS-lens adapter takes 2" filters and the large chip size make me wonder. I've got an adapter coming that will enable me to use the 1.25s, for what I thought would be a temporary measure, thinking I might have to swap my 1.25's for 2's when finances allow, but will be good if I won't have to. Thanks.

Been there, done that, got the T-shirt ...

I enquired, but got no response.

Mmm ... well ... The specifications list the Interface as USB3.0/USB2.0 and looking at the two versions here, I don't see how it provides a USB2.0 connection if it is the older version. But then, it does talk about "guiding" and the newer version does not have a specific guide port (although that can be done through USB). In addition, I don't think they have helped themselves by saying " This product listing is for the COOLED MONOCHROME version of the ASI1600." and then further down talking about " Features of the NEW ZWO ASI1600MC-COOLED "! All-in-all I will adapt to whichever comes. It is, afterall, the sensitivity of the chip/electronics that is the main appeal and, based on the link above, that certainly seems to be identical in both versions. Thanks.

Gina, hope you will forgive me using your thread for a 'headsup', but it is relevant ... 365Astonomy are currently selling the ASI1600MM Cooled for 10% off, i.e. £1184.00 including delivery (that's a saving of £132 on RRP). Stated to be "available now from uk stock", although checking the thread on the supplier reviews board, such statements can be a little inaccurate on occasion. Even so, I thought the saving would be worth having to wait for a week or two if I have to. I wonder if buying an astro-camera has the same effect on the weather as buying a telescope ...

Given your results using the 5nm filter, this must surely be down to the conditions and not the filter (or, worse still, the camera!)?

That's the problem with a lot of the literature that is produced - it assumes a certain level of expertise before you start. Which is probably why I end up asking so many "dumb" questions on SGL.

I've been having a look at the ASI camera specs, and that is one serious piece of kit. It seems to replace everything from a planetary webcam to a DSLR, in one cooled-ccd package, all at a price that is about 70% of the atik-460. You must let us know what the catch is when you find it ...

I am amazed (impressed) by the data you are collecting through your Hα filter with 30s (and now 15s!) exposures. I realise you are using f/2.5, but that is still only about 6x faster than an f/6 scope, and people are always talking about needing 20-30 min exposures, not 3m ones. Is this down to the sensitivity of the camera?

Some nice images starting to come out of this setup now. Are you using the camera lens at its full f/2.5 to get that much data, or have you stopped it down at all? Thanks.