pete_l

In that case smaller is undoubtedly better. With my "octagon" the roof lifts off entirely (small roof, light weight) and there is a removable panel on the south side. So I have all the access I need. And because the walls are so close to the telescope, I can reach in and do whatever is needed, such as initial polar alignment. In fact, I'm in the process of making it smaller! By removing the HEQ5 tripod and replacing it with a pier, I can lop a foot of so off the height, making it even easier to get into.

My imaging ED80 + HEQ5 is a perfect fit in an octagonal "shed" 1.2m x 1.2m But when planning yours, don't forget that the roof has to go somewhere, too!

That was exactly my reaction. The cobwebs aren't too much of an issue, but the rust screams a warning. As you say, it is likely the two presets have corroded. Personally, with a rusty transformer like that, I'd toss the whole thing as it's a hazard. If the transformer core has rusted then there is a chance that moisture has got into the windings. That could compromise the insulation of the primary and cause mains to appear on the low voltage side. I'm sorry to say that if this was mine, even though I have all the test equipment needed to diagnose and fix something like this, it would go straight in the bin for safety reasons.

Personally I think hard-wired cabling is far superior to wireless connections. Better bandwidth, more reliable, no need for yet more kit, cheaper and you can see exactly what is connected and where. Plus, you'll still have to run pwoer cables How about looking into some cable trunking products to tame all the loose wiring?

Check it out for yourself Meade 12 inch ACF Optical Tube Net Weight 56 lb (25.4kg)

A Celestron Edge 11 inch weighs 12.7kg. Compared to a Meade ACF 10 inch that weighs 15kg and the 12 inch which is 25kg. Price-wise a 12 inch Meade costs the same as the 11 inch Celestron, but you'd need a considerably heftier (more expensive) mount to support it. Though when you get to the next step up: both outfits offer a 14 inch. Here both OTAs weigh about the same and the Meade is significantly cheaper. I reckon many people choose by looking at whether they want F/11 or F/8 native, plus what mount they have already and whether they want to spent €3k, €4k €6½k or €9k.

If anyone finds themselves in or near Gorafe in Andalucia on June 1st, there is a stargazing event in the village. They are switching off all the lights and have an organisation bringing in some telescopes for outreach. Briefly, the village (pop. 500) is 850m. ASL and has seeing of about 1 arc-second - give or take

Not as much as you'd think! The QHY8 came out at the end of 2010. It's a 6MPix camera that has 7.8u pixels with a QE of 50-60% and 8-10e of readout noise Compared with a 16200 camera: 4500x3600 6u pixels (so roughly the same FoV as the pixels are just over half the size) a QE of 60% and a readout noise of 9e The significant changes seem to me to be USB3 (only on some versions of the 16200 cameras), weight: 1.3kg vs. 400g, pixel count/size, price: something over twice the price of the QHY8 and an extra 10°C of cooling capability.

To work out where the dust is you could try CCDware's dust donut calculator https://www.ccdware.com/resources/dust.cfm Otherwise, a nice image under difficult circumstances. It's good to see some long FL shots here.

I can't help you. However I have been seriously considering buying their product to replace the ageing and rather clunky Skysensor 2000 on my GPDX. So I'll be watching this thread to see how it goes and whether to proceed, myself. Good luck!

Teleskop Express quote a field diameter of 70mm for their version and 35mm uncorrected.

For the value of the kit you'll have that depends on those bolts staying in place year after year, I'd spend a tenner now on a tube of resin. As Gina says: Ha'porth of tar, and all that

Now would be a very good time to take a full backup!

I get the impression you are taking short sub images without any form of autoguiding. If that is so, then autoguiding would be my first suggestion. Apart from that, I agree with vlaiv's view regarding binning.

The amount of counterweights used to balance a load to not contribute to the specified load of the mount. And, it is better to add an extra counterweight and have then all nearer the centre than to have fewer, further out.

'nuff said! One observation I would make. It appears that one side is heavier than the other. There is an advantage to this in that a slight bias means the worm gear will be better engaged to the RA which might make your tracking smoother.

Is your sky steady enough, often enough, for your imaging to actually attain the theoretical tracking accuracy that either of these mounts say they can give?

There are many issues regarding microstepping that means we cannot rely on it to produce accurate guiding. A problem that increases as the load on the motor increases such as from imbalances or greater inertia from a heavier scope. reference: Microstepping Myths and Realities [ PDF file ] I think I might just have convinced myself that encoders do have a use after all Confused face ---> ?

Yes - better. But even with perfect PA and a rock-solid OTA, if you are ever going to take multi-minute exposures halfway down the sky (i.e. not near the zenith) then encoders alone aren't sufficient to correct for atmospheric refraction. You'll still have to guide. Though I take your point the guiding will only be very light touch.

ISTM that the RMS accuracy of the encoders will easily outperform the variation in star position due to seeing. The encoders should also correct for things like cable drag on the mount, too. The effect of atmospheric refraction won't be corrected by encoders. We are told that +/- 45° from the zenith, this refraction is about 1 arc-min. as a worst case. So starting with an object 45° in the east and imaging until it gets to 45° west, that comes to 120 arc-sec movement from the theoretical position in 6 hours of imaging. On average, 1 arc-sec per 3 minutes of exposure. Though at the zenith there is none and it increases as the object is lower in the sky. Down to about 5 arc-min at the lowest practical limit for imaging. So if you rely on encoders for tracking, even with a perfect PA, you will still see some elongation if you take multi-minute exposures and target objects that are lower in the sky. I think I've just talked myself out of buying a mount with encoders. How did that happen? ?

Yes, that is a big problem. The manufacturers don't seem to go any effort to promote or support their products. They just produce a bunch of marketing photos, some "loading" specifications that nobody trusts, and then toss their mounts over the proverbial wall to an unsuspecting audience. There seems to be no more engagement from the suppliers, they don't take part in any forums, address issues or offer forum-based support. So given that vacuum, it is not surprising when rumour and gossip takes over.

Yes that does look interesting. Especially the new pier. There are a few "elbow" piers availalble, but the ones I have heard about are either made to order for the buyer's latitude or are off the shelf, but are limited to where you can use them I wonder how Mesu is going to handle this? If I can get a meridian-flip free pier for 37° north I might have to re-think all my plans for new toys this year

CMOS cameras can't do hardware binning in the way that CCDs can, That reduces the readout noise from a CCD. But modern CMOS cameras have a much lower read out noise level, so there is an improvement from doing software binning with them. And: yes.

Four gigaBYTES of memory, or 4 gigaBITS (i.e. 512MByte)? The Altair advertisement is not explicit and I doubt there would be any way for a user to tell. Personally I would like to see a photo of the circuit board to validate one or the other.

I built something like this a few years ago. Before you start, make sure that the blocks aren't too wide. I used standard 40 x 20 x 20 blocks. With a small GEM on top, the blocks were too wide to allow a telescope to move unrestricted. There were positions when the OTA would bang into the corners of the blocks.