StuartT

Can someone explain to me what the relationship is between the f ratio of a focal reducer and its effect on the focal length of the telescope? I am seeing some focal reducers described as 0.5x (which I am thinking halves the focal length of your telescope), but others are described by a focal ratio (e.g. a f/6.3 focal reducer). How do I convert one to the other?

Ooh! Thanks everyone. I'd not heard of autostakker. I'll check it out. 😃

I have been trying out Registax on 6 or 7 lunar images (just to see if I can get it working), but I am not managing to get an aligned image when stacking. I'm setting the align points to around 350-400. There is some slight movement in the images (i.e. the moon is not precisely always in the same place in the image), but I assume that's ok. Otherwise what is the 'align' step for? Is there a maximum amount of movement between images that it just won't be able to cope with maybe?

Thanks for the advice everyone, Yes, I must admit that the more I read, the more I think a refractor might be a good way to go. I do have an old achro but it's f/11 so even less suitable! I was looking at the WO Zenithstars - they look nice.

I have a Meade 8" LX-90 (2000mm f/10) but despite that, I'd like to do some astrophotography. So I'm looking to get a focal reducer, 0.5x or even 0.33x Can anyone recommend a really good one? I'm happy to spend over £100 Thanks PS is this the same as a field flattener, or is that different?

Aha! That's a good idea. I didn't think of putting Baader film on my regular finder! Genius ! 🤣

What do people think is a good make of solar finder? Also... this may be a silly question, but how are you supposed to align a solar finder? You can't use a nearby chimney like you would with a finder scope. Thanks

Now why didn't I think of that! Thanks

Quite happy with this new Astronomik CLS filter 300 exposures of 20sec each, ISO400, 11mm lens, f/2.8

This is really helpful. Thanks So I tried using other modes. Manual, Program and Shutter priority (Tv) all produce overexposed images relative to the live view. However, as you say, Av mode produces an exact match for the live view. I can then just use the exposure compensation feature for finer control. Problem solved! I am indebted to you!

Thanks Alan. My 750D doesn't seem to have that option in the menu settings. However, it does show a little icon in the live view window which says "Exp Sim" so I think it's switched on all the time for the 750D. I wonder if the problem is that without a lens attached (just a T adapter) the camera is confused about what aperture is set (the aperture reads 00 on the love view screen)

I use my EOS 750D at prime focus to photograph the sun (either with a Herschel wedge or a Baader solar filter) and I use live view mode to compose the shot. Only problem is that in Manual mode the image changes brightness as you adjust the shutter speed, but it doesn't match the image brightness in the actual photo. It's out by about three stops. So in order to see the sun in the camera's screen, I have to lengthen the shutter speed by about three stops, then remember to dial it down to the actual shutter speed I want before shooting the photo. Anyone know why the display doesn't match the photo? Is there anything I can do to fix it?

Took these today with my 90cm f/11 achro, Herschel wedge, a 2x Barlow and a Canon EOS750D Unfiltered was 1/500 sec at ISO100, the other one is a solar continuum filter and polariser (1/15 sec, ISO400). Not great seeing. A little hazy.

Aha! There's always a reason for things 😉 Thanks. A tip from Mr Tonkin is to flip the binoculars around 180 in the vertical axis so your tripod's pan/tilt handle points forward. It means it doesn't get in the way of the tripod legs when looking at high elevations

Yes, fair comment. When they are set, they are set. Infinity is infinity.

One slightly annoying feature of the APM binoculars is that each eye focuses separately. This is rather fiddly. I'd much prefer a central focuser and a right eye diopter adjustment. That way, once you've adjusted the diopter, you only have to focus once. Not sure why they've done it like that, but I guess I'll get used to it

Thanks so much everyone. This has been really useful. In the end I have gone with the with Manfrotto 290 monopod and a trigger type head https://www.amazon.co.uk/gp/product/B001B0C2S6/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Is a monopod stable enough? (With only one leg) also, don’t monopods already have heads? I’m interested in why you recommend a head from a tripod instead? sorry for the basic questions!

Just took delivery of a pair of APM 16x70 ED APOs and trying them out on my crappy Velbon EF-61 camera tripod just ain't cutting it, frankly. Suggestions welcome!

Based on the review posted above from Cloudy Nights, I decided to buy the APM 16x70 ED APO instead. They just arrived and I look forward to trying them out. Easier to handhold and the lower magnification is preferable for general observing, I think.

I was interested to read this statement in the review posted by Neil Phillips. A note here about the Skymaster and the Skymaster Pro: the only clearly recognizable difference I found between the two consists of a brighter image in the Pro version; in all other respects, the Pro did not do substantially better than the basic Skymaster.

really? they are not much more expensive, I see. In what way are they superior?

they were brand new. So I may just send them back. That video is for a different model. Mine don't seem to have collimation screws visible

hmm.. ok. Thanks. Slightly depressing. I found this video

Ok, so we had a bit of clear tonight and I tried them out. But I am seeing a double image. I was looking at Arcturus (as a very obvious target). Whatever I do (adjusting the eye width, the diopter adjuster in the right eyepiece) I can't get a single image. And I'm talking about a big separation - about 1/3 of the entire field of view Any ideas?