On 06/05/2022 at 10:11, FLO said:

As you observe, you can also listen to hundreds of audio descriptions and view detailed information about thousands of objects within the app’s database. 

 

 

Oh no, please, No! It'll be like using a self-service checkout at Tesco! Can you imagine several of these at a star party all with audio commentary turned on? Other than that it looks like a great idea.

On 12/04/2022 at 09:06, tomato said:

What kind of grease do you use on those gears and bearings at 40 below, and do you switch off the Peltier coolers?

If you reverse the supply polarity it will warm the CCD to bring it up to "normal" cooled operating temperature!

17 minutes ago, mcrowle said:

Actually, it was wulfrun with those suggestions, but fingers-crossed we all get a chance to practice our lunar imaging on the eclipse next Monday morning. Going to be tricky, though, with the Moon so low in advancing twilight!

Regard, Mike.

Sorry, Mike, I don't know how I got the two of you mixed up there! I have my new iOptron Rc6 all nice and ready for the eclipse, but still struggling to get decent results out of it. I have it on a heavy photo tripod with a Nikon D800 hanging off the back end, so it is really unbalanced. The tripod wedge is fixed to the dovetail with a single screw at the back end and it wobbles like a blancmange! I can't seem to get critical focus, yet, but am still hoping to capture that eclipse, so you now know it will be cloudy right through and can blame me! Good luck with capturing it: I look forward to seeing the photos.

Definitely the British weather, especially clouds. We went to France for the 1999 total solar eclipse in the mistaken belief that this would remove the problem and found a lovely spot to set up, with not a cloud in sight. Until ... a few moments before totality when clouds started forming right next to the Sun with it too late to move. The Sun remained blocked out for the duration of totality with the clouds completely dissipating within a couple of minutes of it ending! So, it's not just Britain where the weather screws up our observing!

I transport my Dob in a Land Rover Discovery and can confirm that and unequal split rear seat helps a lot for this. Obviously, you could run into problems with LEZ with Land Rovers and it is probably not the type of vehicle you are looking for. If I was after a car to do this I would look at the type of thing that gets converted for wheelchair access, things like the Citroen Berlingo as they have higher roofs than normal cars. It might be worth speaking to your local disability car supplier for advice.

Have you considered photographing the quarter Moon? Shadows are very short on the full Moon, so little detail shows, whereas on crescent, quarter and gibbous, at the terminator, the shadows are long and the detail is crisp. Motion blur is commonly caused by a setup which is insufficiently rigid coupled with a shutter speed that is too long. As Mike says, open up the aperture and crank the ISO up, which will also allow you to use faster shutter speeds. I shot the Moon last night at ISO 800, f/9 and 1/250.

You could also try eyepiece projection if you don't have or want to by a barlow, although the barlow will make life easier.

Someone has already suggested Making Every Photon Count, so I'll add Astrophotography by Thierry Legault. It covers an awful lot and in good depth.

On 30/03/2022 at 11:07, StuartT said:

Do any of you have good tips on astrophotography books? I have a reasonable level experience now, so I am not looking for a basic introductory text, but rather something more definitive and comprehensive.

How about this one? The Astrophotography Manual by Chris Woodhouse.

Suggestions welcome!

Thanks

I have Astrophotography by Thierry Legault. I don't know if you would consider that the appropriate level, but he is an engineer and discusses things in quite some depth.

7 minutes ago, M40 said:

Many moons ago, I used to work for a company called Satchwell, wholly owned by GEC. GEC applied a very strict regime of a minimum gross margin. Time goes by, a few GEC directors changed and with it the GEC policy. The GEC money mountain was consigned to history as was Satchwell. I think that you will see gross margins maintained or the businesses will go to the wall. Not good news for us, but I would rather save for my toys a little longer than see companies disappear.

This illustrates my point nicely. I have been in business for more than 25 years and never work on the basis of undercutting the competition. I've seen far too many businesses go to the wall by failing to maintain margins. On the same principle, recessions serve a purpose by getting rid of poor businesses that do a great deal of damage to marketplace. If your business can survive a recession, it will come out the other side with greater potential for profits as much of the low-price competitors will have gone to the wall. Of course, if you can lower prices without lowering margins or profitability, through technological innovation, etc, then by all means do so.

18 hours ago, OK Apricot said:

I've always wondered why, in this situation, a company wouldn't keep their prices lower than a competitor. Assuming margins are similar, surely a company selling the same product at a lower price will move more of those products, and make more money as a result? 

Competing by undercutting prices is a potentially dangerous tactic which can start a price war that leads to no-one making money. This is Economics 101. The better thing to do, as a manufacturer, is to keep your prices slightly above the competition and focus on quality and benefits to the customer.

14 minutes ago, michael.h.f.wilkinson said:

I have the ASI178MM and use it a lot at 480 mm focal length for full disk imaging in white light and Ca-K. If your reducer doesn't add a lot of aberration your combo should work.

Hi Michael

Thank you. That is what I want to know. Is it likely to be OK for H-alpha with my Solar scope? My reducer is this one:

https://www.rothervalleyoptics.co.uk/antares-05x-focal-reducer-125.html

Obviously, I can adjust it's position with extension tubes to minimise aberration and tweak the focal length a bit.

Mandy

Thanks for the explanation, johninderby. That makes sense. I'll be using mine in the H-alpha and a Skywatcher 250PX with 1200 mm focal length, so it could be an OK match. I take on board your comments about the focal reducer and the bigger pixels of the 290, but what I really need is the larger sensor in the 178 to fit the entire Solar disc on with 0.5X reducer.

From my research, it appears that the 178 does do binning. Here is the relevent section from the manual:

"6.6Binning  The ASI178 camera supports hardware bin2 and bin4 mode. The ASI178 camera supports software bin2, bin3 and bin4 mode. Hardware binning is supported by sensor but is done in digital domain like software binning and use 10bit ADC. The only advantage of hardware binning is faster fps. We recommend customer to use software binning if you don’t care speed. "

Thanks again.

Mandy

I'm confused. Why do you suggest that the 290 is better suited to longer focal lengths? From my research it has a smaller sensor than the 178 (1/2.8 against 1/1.8). I'm also not sure what the effective focal ratio of f/15.5 has to do with it. Surely what matters is the effective focal length or am I somehow getting confused?

It looks like you have an interesting setup, there. I guess that is a geared stepper motor you are using for focussing with an inside-out timing belt around the barrel to act as a matching gear. I need something to focus my 800 mm mirror lens, so I might look at doing the same.

Thanks for your reply. Cloud Bringer makes me smile. I've seen no blue sky since I got my new scope.

I've just bought a Daystar Solar Scout 60mm DS for H-alpha imaging of the Sun. I am now looking for a suitable camera to use with it. I know I could use my DSLR, but for H-alpha that is not going to give best results, so am looking for a dedicated monochrome imaging camera. I have identified the ZWO ASI178MM as a possibility that fits my budget and has a large enough (I think) sensor to image the entire Solar disc if I use a 0.5 focal reducer which will give me a total focal length of 465 mm.

Does anyone have any experience of this camera in this application, or know if it will be suitable? I know it does not have an IR blocking filter, which I understand is an advantage for H-alpha. The spec is available here:

https://www.rothervalleyoptics.co.uk/zwo-asi178mm-usb-30-monochrome-cmos-camera.html

Thanks

Mandy

I've just bought a Daystar Solar Scout 60mm DS for H-alpha imaging of the Sun. I am now looking for a suitable camera to use with it. I know I could use my DSLR, but for H-alpha that is not going to give best results, so am looking for a dedicated monochrome imaging camera. I have identified the ZWO ASI178MM as a possibility that fits my budget and has a large enough (I think) sensor to image the entire Solar disc if I use a 0.5 focal reducer which will give me a total focal length of 465 mm.

Does anyone have any experience of this camera in this application, or know if it will be suitable? I know it does not have an IR blocking filter, which I understand is an advantage for H-alpha. The spec is available here:

https://www.rothervalleyoptics.co.uk/zwo-asi178mm-usb-30-monochrome-cmos-camera.html

Thanks

Mandy