skybadger

Yes

There's a good guide to peltier calculations on the rswww.com website.

Did you see the strange bright thing on the limb, it looked like a spot but it was bright rather than dark and raised above the edge, but showed no real prominences.odd !

Mine did, they both fitted the same eq5 (IE vixen hal110 )tripod.

Really nice. Like that!

I was out in person last night and saw nothing but a glorious sporadic. Passing cloud with large haps was the order of the night. Packed in about 0115 BST.

I detected 6 meteors brighter than mag4 in 2 HR slot around midnight of which maybe 3 radiate from the expected radiant. Got a really nice sporadic though.

That's cos win10 supports 64 and 32 bit.

Yes, this would always be closed cycle.

I have a na140sf and a vixen visac, both of which have tertiary optics that I wouldn't use for solar observing for the reasons above. However I did find, purchase and try a 80mm halpha 35nm filter on AliExpress for a reasonable price that I now use as an erf to prevent self heating driving my quark off band. My trial with a 1.25" ha pre filter for energy rejection lead to reduction in detail which I'm not seeing with the bigger filter.

Hi all. I bought a water-cooled Atik 11k secondhand camera recently and while it cools down to useable temperatures without water-cooling, I'd really like to try a good water chiller on it to get the best performance, even during summer. I'm thinking how to mount the cooling,pumping and reservoir kit near the scope so I thought to check first here. Is anyone using water cooled cameras, what cooler systems are in use, how did you located the cooler , what sort of performance did you get ? I have a Reservator XT cooler which came with the camera and its massive and probably doesn't have the head for cooling the camera on the mount while sitting on the floor. Currently I'm in the degassing stage of prepping it , now I have replaced the worn orings and for some long pipes. Really considering active chilling via water rather than just heat transfer but looking for experiences ! Thanks in advance Mike

You could try here. https://www.antaresoptics.com/SEMirrors.php I have one on my 12" bought through eboy several years ago. Good quality and value.

Sounds like Dec and or ra were inverted . You haven't mentioned calibration and what that was like ?

I can do that. Good suggestions all round. Thanks for your input. I'll report back how I get on. Probably at the weekend.

I have a 6" optical flat and a 12" plate blank which I can try with.

Yes, but I need to get to a place to start from, where I know the infinity focus is the prescription distance behind the primary which I can then adjust if necessary using a ronchi to check. The deviation from prescription should be small. You also incur spherical aberration for objects closer than infinity. This is all about getting to a starting point on the bench to setup for a night of checking and adjusting using the stars later, hopefully as little as possible. It's a good point about using a point and a knife edge though. It comes back to whether I can position it on the optical axis well enough. Thanks

Here's my contribution to this - seen from RIseley in South Berks /Hampshire border south of Reading, at 29 April 2302 to 2309Z. North is 20 degrees from top towards E, South is 20 degrees from bottom towards W. All SKy camera takes exposures for 5 seconds every 5 seconds with a 50ms delay for read from an ASI 120mm camera. I'll have a fully annotated video once ASC processes it. 2022Apr29 2302_2309Z 2nd stage capture.avi (205MB) 2022Apr29 2302_2309Z 2nd stage capture.avi

I thought about the seconds scope but that requires you to have solved the same problem in the absence of stars -exactly knowing where infinity focus is. I also thought about the latter. Bringing objects closer from infinity it's possible to calculate the actual position of focus but it will be quite a way away and is hard to cobble together a set of extensions for and isn't a definitive yes/no I'm looking for. The ultimate aim is to set the viewpoint at the back focus distance and adjust the mirror separation to obtain focus. Cheers Vlav.

I am trying to find the actual back focus distance on my homemade RC without pointing at a real star and facing the problem that focusing on anything else results in focus at a significan distance from infinity focus. I had the bright idea of putting a synthetic star in the eyepiece next to a viewing hole and a large optical flat at the end of the scope. My thinking is that the point source, when at the infinity focus point, will be made parallel by the scope, which will reflect off the flat and come back to a focus at the viewing hole. If it's inside focus I think the telescope will present a convergent bean to the flat and it will come back as a donut. For outside focus, it will be convergent and also be a donut. Moving through actual focus will cause the image of the star to come to focus at the infinity position. Is this correct ? Is this the standard null test ?

I'm struggling to find that large angle. Bracket, have you a link please ?

I had eye surgery for this and other reasons more than 10years ago. It was the type where they remove a layer of cornea to make the optical corrections. 10 years on, one remains practically perfect and the other has some astigmatism again. Sadly instead of bilateral full correction they gave me monovision where one eye is made perfect for distance and one for the middle distance.which is not what I wanted. So I find myself wearing screen glasses and some for close up work like with a soldering iron. This seems quite different than replacing the lens like you are mentioning. I dont think there is a problem with being a high street place I think the risk is that you get rushed at the last minute and you don't get the level of follow up you need. I have traded astigmatism for a small degree of halo under fairly rare circumstances. I also feel my dusk eyesight is weaker. Im an archer used to shooting all day into dusk and now have difficulty resolving that target detail under low dusk light. Maybe that's age though.

I am looking to understand my options for putting a more weight capable focuser on the back of my homemade 12" RC. I am currently using a 2" Revelation crayford type focuser. Having upgraded my camera to a new 2nd hand Atik11, that focuser just cant hold the weight. So I need a new focuser. That focuser has a 60mm thread on the back to fasten it to the scope focuser plate which I made on the lathe. My question is really about what size interface or extension pieces are commonly available commercially or through materials supplies for me to manufacture ? Which drives me to picking a standard size of fittings. If I put a Baader steel track on there, that focuser has a 90mm diameter dovetail that can fit on a 68mm thread but the Lyra RC scopes often use 100mm diameter extension tubes and there aren't many of them about. Is there a source of extension tubes I can adopt that are fairly common ? Are there other focusers that also fit the bill? If there aren't, my thinking is that I'll have to make them and that's a chunk of metal to turn, 90mm being an unusual tube size too. Has anyone fit a refractor focuser (with extension tubes to take the longer focuser tube) or are there reasons not to do that ? I reckon I have about 180mm of focus depth available to fit this in, even when using a reducer.

That sounds like it may be the cabling at fault. I.e. they are dragging or adding vibration. To prevent that they could be tied to the mount and brought back along the axles to ensure they don't pull.

Take it apart, mark the edges for assembly order and orientation and the use a mixture of deionised water, a few drops of lemon juice, a few drops of vinegar and a drop of washing up liquid to gently wash the mould off. If works a treat. Follow with a wash in alcohol and reassemble.

That looks like it. I'd like to know why there is such a difference in basis for the prediction. But it is a big difference.