SmoothOperator

3 minutes ago, Dave scutt said:

That's the one it should tighten or loosen the focuser movement. 

Dave

You legend, thanks a lot for the help buddy!

6 minutes ago, Dave scutt said:

Hi SmoothOperater.

I can't see from the picture,  is there a grub screw just below the locking bolt .

That will tighten or loosen the focuser..

Dave

 

Hi Dave.

thanks a lot for the quick reply!

There is a small black grub screw below the locking bolt, is this the baby?

Hi guys hope you are all well!

im a beginner stargazer with a skywatcher 200p. As a beginner I haven’t tinkered with the scope at all however I’m having an issue with the focuser where when I adjust it outwards the tube will slide back down making focusing very annoying. There is a locking bolt to hold the focuser in place but this disengages the adjusters so once locked cannot be adjusted anymore. I can’t see anything obvious such as a loose bolt so any suggestions on how to fix this?

any help is much appreciated, thanks in advance

3 hours ago, Louis D said:

Generally, about 30x per inch is what I figure for Newtonians, so about 240x max for your 8", which is where you are today.  The secondary obstruction and spider vanes tend to cut down on contrast at higher powers relative to an APO of equal aperture.

In particular, you'll be severely limited by UK seeing conditions, so 100x to 150x might be more realistic for Jupiter in particular.  Do you notice more detail in Jupiter at 240x than at 120x or are they simply bigger and more washed out?

Saturn's rings and Mars can take more power due to being of higher contrast.  On high contrast objects like double stars, you can try to push 300x or more.  If you want to go for 400x, I would recommend a 12" scope minimum and steady seeing conditions.

More expensive eyepieces have better lens polish leading to less scatter, better multicoatings, better stray light control, and wider and better corrected fields of view (especially in scopes faster than f/8 such as your own).  However, on axis, a well executed, cheap eyepiece can still perform very well.  Mainly, contrast and resolution on planets will suffer a bit.

Also, based on what you’ve said would you suggest that instead of spending the money on the EP set in the URL I’ve copied or would it be better to spend it on a decent 8mm eyepiece which combined with the Barlow lens will give me my 300x mag?

59 minutes ago, Louis D said:

Generally, about 30x per inch is what I figure for Newtonians, so about 240x max for your 8", which is where you are today.  The secondary obstruction and spider vanes tend to cut down on contrast at higher powers relative to an APO of equal aperture.

In particular, you'll be severely limited by UK seeing conditions, so 100x to 150x might be more realistic for Jupiter in particular.  Do you notice more detail in Jupiter at 240x than at 120x or are they simply bigger and more washed out?

Saturn's rings and Mars can take more power due to being of higher contrast.  On high contrast objects like double stars, you can try to push 300x or more.  If you want to go for 400x, I would recommend a 12" scope minimum and steady seeing conditions.

More expensive eyepieces have better lens polish leading to less scatter, better multicoatings, better stray light control, and wider and better corrected fields of view (especially in scopes faster than f/8 such as your own).  However, on axis, a well executed, cheap eyepiece can still perform very well.  Mainly, contrast and resolution on planets will suffer a bit.

Oh okay my mistake, I’d read it was 50 x the aperture. So when viewing Jupiter I can definitely notice more detail when swapping to 240x just an adjustment of the focused. You’ll have to forgive me as I’m a bit of a novice and I don’t fully understand some of the language you’ve used like corrected field of view, what sort of effect does this have when looking through the eyepiece as opposed to an Uncorrected field of view?

thanks for the info on eyepieces also, much appreciated.

So I’ve had my skyliner 200p dob For just over a year now and couldn’t be happier with it as my first scope. With the scope came a 10mm and 25mm eyepiece and I also purchased a cheap Barlow lense to go with it. On a good night with the 10mm and Barlow I have managed to get some stunning views of Saturn, making out the gap between the planet and ring clearly as well as seeing the coloured cloud stripes of Jupiter. Im now looking to expand my EP collection and have done some calculations. Based on my scope I believe the maximum magnification I can achieve is x403 and with a 6mm EP and Barlow would be able to achieve x400 magnification. Although this is within my maximum magnification can anyone offer an opinion on whether this means I’d be able to focus the image correctly or whether it’d just be a blurred image. Also by spending the extra money how much difference can be noticed with the same sized EP, for example would a £150 EP really offer much more than a £25 EP it terms of image quality. FLO sell a plossl EP set which comes with a 6,8,13,17 and 32mm EP as well as various filters and at first glance looks well worth  it but not entirely sure on whether it’ll offer more variety in my observing sessions. Guess I’m just looking for an opinion on where to go next as I’m a bit lost in the sheer number of different options.

https://www.firstlightoptics.com/eyepiece-sets/celestron-eyeopener-eyepiece-and-filter-kit.html

On 20/07/2020 at 10:32, Msraa said:

I tried to take two pics as i thought it was a planet rather than a star. The one, that was taken early morning, I focused my phone camera pointing towards south east at 3.10am and the night pic was taken pointing north east at 11.45pm. Can someone advise me whether these are planets. If yes, is it possible to identify which planets by looking at it? 

I’ve been observing Saturn and Jupiter over the past few night and can get lovely sights of them both. I use an app in my iPhone called Skyview which is basically an augmented view of the universe based on your current location. Really easy to use and make planning observing sessions quick and easy. Also very easy to use in order to identify things you are looking at, simply point your phone at it.

As a beginner I use the skyliner 200p dob myself and couldn’t  be happier with it as a first scope. Stays in the conservatory where I can have it out in the garden and setup for viewing in minutes.

23 minutes ago, Moonshane said:

I actually think you can use acetone for stubborn mainly greasy marks but I've never found the need.

http://www.rfroyce.com/cleaning_new.htm#:~:text=Pour some acetone on the,of the dirt and crud.

Very interesting read, was surprised to read that acetone wouldn’t cause any damage to the coating. I think as a beginner astronomer I I hold it in my head that mirrors should always be perfect but just overreacted to a piece of dust. Will definitely take a few things away from that post though so much appreciated. 

5 minutes ago, Moonshane said:

I agree that mirrors should only be washed very carefully and if required. Yours sounds very normal and is unlikely to be badly affected.

The mirrors are coated with a few atoms thick coating to achieve the reflectivity and this is easily scratched. A scratch would affect the view more than a sfew dust specks.

All that said, cleaning them is easy with care

 

Oh okay that’s a relief then. I did wonder about a coating on the mirrors and so I believe acetone would actually damage this layer then. Many thanks for the help also.

3 minutes ago, banjaxed said:

If you do a search for ‘cleaning a primary mirror there are lots of suggestions. When I cleaned mine I removed the primary mirror and cell any put it in a bowl of clean water then added a little washing up liquid on to the mirror and very gently rubbed it  with my finger. After you are satisfied it is clean rinse the mirror with distilled water and prop the mirror and cell on its side and allow to drain.

Thanks very much amigo, very much appreciated!

16 minutes ago, banjaxed said:

If you only have a few specks on the mirror I would leave it alone as they will not have a detrimental effect on your viewing. I have only cleaned my Skywatcher 8” Dob once and that was only because I thought it had some fungus on it which turned out to be funny coloured dust.

Hey thanks for the advice, much appreciated. I’ve had mine just over a year but I was using it a few nights ago just to look at Jupiter and noticed a fairly large spec but like you said i don’t think it affected my viewing, I was slightly concerned though as this was the first time I’d noticed my mirrors looking anything but perfect. Sounds stupid but if my mirrors only gradually build up with dust so my viewing is only very gradually affected, at what point would you decide to clean them? And what with?

Hey there, I’m looking for some advice/assistance in the cleaning of the mirror of my telescope. I have an 8” skywatcher skyliner 200p dob and have noticed a few specs on the primary mirror however I’ve never attempted to clean the mirrors before and I’m unsure on what substance to use to actually clean it. I have some acetone which I can grab from work but I’m not sure if this will be too harsh and diminish the reflective finish. Also does anyone know if the mirrors on this scope have a mirror finish or if they are coated to produce the finish.

thanks for any help!