Mike_S

This seems to go against the theory of the aperture mask? Or am so reading it wrong?

What is the advantage over a faster or slower apo? Maximum power?

i’m confused about these dob masks now. One of the links appears to suggest it’s a myth that it would improve the view. 

16 minutes ago, Stu said:

Freddie, I believe the Lyra Optics, TS and Altair 102mm f11 clones are all pretty good these days. I think that's what I would try in this position, or a Tal 100RS which can be picked up pretty cheaply and have good correction at f10 and have a good reputation.

Have you got a link to these please? I thought they were Apo’s considering the price unless I’m looking at the wrong ones. 

Thanks. I’m holding back on an Apo purely because of the cost but also the mount as I don’t have one. I’m going to take a few months experimenting and eventually may  try a different telescope. See what comes up second hand. I almost bought an F11 Celestron Astromaster before the dob but they’re discontinued now. Nearest appears to be the F10 SW Evostar. I’m glad I got the dob, it’s just a steep but fun learning curve. I was wanting to upgrade it to a 12 inch as I do like the dob. Want to get better with my current one first though. 

Thanks for very thorough replies. A lot to take in but I do like the science and maths side. It’s still tough to work out to me if a 4 inch frac of any quality will outperform my 10 inch dob. Perhaps if they were closer in size? My collimation might not be the best. I just do it with a collimation cap followed by a star test. I plan on trying a Cheshire eyepiece but I can’t see anything wrong with the star test so haven’t bothered buying new collimating equipment. 

I’m definitively going to try magnification of around X 170-200 but it was the same with much lower (X 120). I’m going to try moon filters as well. 

I feel like buying a cheap refractor for £150 just to try and that would rule out problems with my mirror or collimation if it’s the same. 

So what is the advantage in a 4 inch frac even an apo over a 10 inch dob? Is it just because they are easier to use on an EQ mount for imaging?

Are reflectors more affected by atmosphere turbulance than refractors? Is there something about a lens that has a viewing quality advantage over a mirror?

I was thinking the slower F ratio frac would not suffer from chromatic aberration. I didn’t know that slower can also improve the view through reflectors to ED quality.

Thanks I never heard of aperture mask. I don’t know a lot and thought more was better. Worth a go. I think my magnifications may have been too high so I’m going to try inbetween. Tried X 129, 240 and 342. I want to get more eye pieces to try 170-200. Problem is it’s just basically a bright ball of light for Jupiter. Saturn is okay, a bit bright still perhaps. Have a neodymium filter but will try a moon filter next time too.

Yes U.K. skies suffering from low planets. 

What is a decent AZ mount for 100mm Apo’s? If I go this route it will have to be used especially as I’ll sell it if no improvement.

with an ordinary Achro I could just keep it as a travel scope as they’re only cheap and might tell me if my problems are relating to my other scope if I can see more detail or colour with it. 

Sorry been discussing this in another post but thought best to do a new one for it. I have an F4.7  254mm diamater dob. Trying to improve my views of Saturn and Jupiter at the moment. Wondering if perhaps I would get a better view from a refractor and if so, is an F10 90mm Achromatic worth a go such as the SkyWatcher Evostar 90 or only if I spend more on a 100mm F9 Apochromatic like the SkyWatcher Evostar 100 ED DS Pro? I don't really want to spend money on an expensive EQ mount when I'm just doing visual and a bit of smartphone snapping. 

I’ll keep a look out second hand. Thanks. I was thinking a cheap achro might be okay if it’s a high focul ratio like F10. 

31 minutes ago, John said:

Since Jupiter has been low down I've found my smaller aperture refractors have delivered better sharpness and contrast than my big 12 inch dob. When it's high in the sky again the dob will shine

John I’ve been wondering that too and tempted to buy a cheap refractor like an Evostar 90 just to see the difference. Why would this be?

Thanks. Ive got a cheap moon filter I’ll try next. If it’s an improvement I might order more moon filters or a variable polariser to try. 

Hi,

i have a Baader neodymium filter but Jupiter still just appears as mostly a white bright ball. I am working through issues. I got a bit of detail out the other night when I could see faint bands after more patience. Not noticed any details with filter in or out but could moon filters help? Like one of these? I know the planet is low. Have a 10 inch dob and tried with a mixture of Pentax XW, Myriad XWA’s and cheap plossls on a range of magnifications, X 120, 240 and 342. Will be trying eyepieces inbetween soon of around X 170-200.

https://www.firstlightoptics.com/moon-neutral-density-filters/baader-neutral-density-moon-filters.html

Thanks I have nightcap camera that is quite slow. Will try procam 5 or 6. 

25 minutes ago, happy-kat said:

Hi

Have you seen this section you might find the posts members made interesting.

https://stargazerslounge.com/forum/236-imaging-challenge-10-smartphones-tablets-now-closed/

 

Thank you, no I shall have a look now. I’ve just been googling articles.

Hi,

i’ve been using iPhone camera and the NightCap camera app. I’ve only just realised I should adjust ISO and shutter speed to stop planets being so bright and featureless. Just some questions I’m struggling with if you would be kind enough to help please. 

1. Is there like an eye relief but for the phone camera lens/how far do you position the camera from the eyepiece?

2. Do you adjust ISO then shutter speed? Any more tips?

3. What are your favourite eyepieces to use with this? I have the NexYZ smartphone adaptor. Using it with Myriad XWA and Pentax XW eyepieces on a 1200x254 dob.

4. Have you got your best images with a smartphone from a reflector or refractor? Add more detail if you wish.

5. Do you usually do single shots or videos?

any other tips would be welcome, especially on mounting and positioning the camera. 

11 hours ago, Piero said:

Personally, I wouldn't use those eyepieces with a barlow. They tend to be too heavy and tall.

Aside from optics, in my opinion the eye rubber design of the Lunt APM is much better than its counterparts. I actually prefer that design to those installed in the TV eyepieces I tried.

Thanks that’s good to know. What do you use inbetween the 5 and 9mm?

Oh I see. I’m still waiting for a used Pentax XW7mm that will do instead. Kicking myself I didnt snap one up when I bought my 5mm as they were selling a 7mm as well. 

I have these too and going to order the 13mm soon for the complete set. What Barlow would you reccommend with them? APM Lunt sell one. 

I’m quite new to this hobby. Have a 10 inch dob but want a 12. I don’t want to go much lower than F5. I don’t have much time to do this and don’t want to be spending over £300 on an eyepiece. Not that you would have to but I keep hearing of issues that I’m just not noticing now in my F4.7. Larger than 12 inch and F5 then the focul length is perhaps too long for some situations? I even got a 30mm eyepiece for a wider field of view. If my focul length was much longer then field of view won’t be great and I really need it as I’m struggling finding stuff being a beginner. Also I’m happy with my solid tube and don’t fancy creating more problems with a truss. 300x1500mm solid tube would be max for me.

Ive got the full set of Myriads now. Havent used them a lot but they were too good not to snap up at £166 each. I will get the APM Lunt 13mm version as well and I hear they are bringing out a 7mm which was meant to come out early this year but no sign yet. 

5000. 

Been offered a 6.7mm Meade 82 degrees second hand. Good to hear they are good.