andrew s

I have been imaging in Castillejar all summer and my kit is next to theirs. It maybe that @FLO have been too busy with orders to process their images. Regards Andrew

100% agree with me as I voted first 😛 Regards Andrew

I think it does hold up quite well . I will try to find the published research papers I read some years ago that supported this view. Do you know of any pubished evidence against it or have you perhaps studied it? On comparing refractors and reflectors I think you need to look at why the best planetary images are from those terrible SCTs. Yes you need a larger reflector to give the same resolution as a refractor that's physics and well understood. It is interesting aside to note P Lowell tended to stop down the 24" refractor for his observations. On resolution, while the resolution limit is a convention it applies to reflectors and refractors alike. Physics limits what can be seen even if you don't belive it. Small telescope have a more limited resolution than larger ones (assuming any central obstruction is accounted for correctly). There is no magic in optics. I never claimed telescopes produced a pixelated image just used that as an example of where we tend to prefer small and sharp as to large and more blured. Just as you find a natural preferred magnification not too high and not too low. So I have bitten back😜 Regards Andrew PS I have tried to track down the papers I read years ago but it was in the age of getting paper copies via the library! However, the Fried parameter is alive and well and the following might be worth a look. https://www.telescope-optics.net/induced.htm https://www.handprint.com/ASTRO/seeing1.html https://www.handprint.com/ASTRO/seeing2.html https://www.handprint.com/ASTRO/seeing3.html and references their in. Simple view here https://skyandtelescope.org/astronomy-equipment/beating-the-seeing/#:~:text=So will every other telescope,after bringing a telescope outdoors. Most modern references concentrate on adaptive optics but the Fried parameter (https://en.wikipedia.org/wiki/Fried_parameter ) still persists.

That won't do at all Spot is a dog. See Spot the Dog series of books. Regards Andrew

Don't tempt me..... Regards Andrew

Is that really true @JeremyS.? In a moment of exquisite seeing the atmospheric dispersion should, if you have sufficient resolution and magnification, be most obvious. The visual equivalent to lucky imaging. I grant that adjusting an ADC in poor seeing would be problematic if not impossible. However, I can't escape the idea (pedudice) that small scope preference in poor condition is due to the observer preferring an unresolved smaller shifting image to a resolved larger dynamically blurring one. (Cell size above or below instrument aperture) Much as one pulls away from a pixelated image to see the whole. Regards Andrew

£64.99 on Amazon Regards Andrew

I'm Sorry, Dave... ... I can't do that. Oh yes I can, nice captures Regards Andrew

Looks like I might be able pick up an as new copy at a good price soon.😊 Regards Andrew PS @johninderby seriously I would be interested in an excellent condition copy..

Maybe you could do a flash card version?🤔😂 I suspect it being in 3 volumes might have been a bit of a giveaway . Regards Andrew

Welcome, you should have the skies for it. Regards Andrew

Well I downloaded your image and low and behold it is saturated. The flat top is a giveaway. Always best to measure not assume. Regards Andrew

Mine is fitted between the camera and the filter wheel as I use a SA200 diffraction grating in the wheel and I have to be able to align the spectra to the camera. I do have vignetting but this is due to the spectrograph as a whole. The rotator is well designed and I don't think it will give you a problem tilt or weight wise in either position. Regards Andrew

Are you sure the Sadr is not saturated? Regards Andrew

The EFW is T2 which is m42 0.75mm pitch. I use the Teleskop Services TST2Rot. Regards Andrew

There are a number of "T2 rotation adapters" just Google. I use one with my ASI 1600 without problems. Regards Andrew

I always find joy and inspiration in the complex slightly oily surface of our planet to the vastness of the Universe and the miniature of the sub atomic . The fact that we can comprehend so much of its constituent parts and how they work is another wonder. Regards Andrew

A poor life, this if, so full of care, We have no time to stand and stare. W H Davies Regards Andrew

Provided you have enough back focus yes. However, you might want to use a Barlow to increase the image scale, for the planets but the following gets harder. Regards Andrew

Rather a nice composition. Regards Andrew

Glass path corrector used with bino viewer I think. Regards Andrew

I don't think it's a good idea for visual work. Most reducer are either rather crude or designed for imaging. Better to use longer fl eyepiece and Barlow than the reverse. There are good optical reasons it's not commonly done. Regards Andrew

@Alan White so if I understand correctly the pier will go leaving a pad. The Dobsonian will fit the pad. So far so good. How about reengineering the pier to stand on the pad. The AP design is simple and strong and I am sure there are others. Regards Andrew

I think you did a commendable job given the locations constraints. Regards Andrew

Yum yum. Regards Andrew