Reflections of a new Dob owner (no pun intended ;))

[Raj (Raj)]

Hi Raj here,

So a few weeks ago I decided to take the plunge and buy a telescope of my own. I have the privilege of being able to head down to Wye River regularly on the Great Ocean Road in Victoria. A friend loaned me her 'supermarket' budget refractor (60mm aperture, 700mm fl) for a play. I couldn't see anything at all to start with and effectively dismantled it all (somewhat) gave it a clean and put it back together, and then we had some success.

So, it comes with rather crappy looking 20, 10 and 4mm EPs. I enjoyed what I saw but overall it was (expectedly) pretty crappy experience. Fast forward a month or so.

I've done A LOT of reading. The forums, articles, advices etc are very very helpful and much appreciated (thanks in advance) So on all that advice I decided to grab an 8" Saxon Dob (collapsible)!

I managed to get what looked like a very well looked after scope. Original receipt indicated it was only about 6 months old which confirmed the previous owner's remarks. Only used a couple of time, seemed true. So, a bit less than what I would pay new, I was a happy newbie astronomer.

It comes with blanket 10 and 25mm possl EPs. When I got a first look from central Melbourne at the moon I was blown away. Clarity is nuts. Then I hit Jupiter. So excited. Moved it down to Wye River and again, have had some real fun. Have seen Saturn and 'ooh aah'd at lots of stars.

But i don't get to see much color, which I now understand a bit more is unlikely (impossible?) with just viasual observing and an 8". And I struggle with things other than the brightest of stars and the planets. I've read an 8" should get me the Cassini division and M42 pretty clearly, but I merely see splodges My g/f seems to see things better, and I admit I wear glasses, but I'm not sure I'm really seeing all that I could. I also have a pair of Bushnell 10x42 binos, which should help, and they do make the night sky look pretty but I don't get the impression I'm seeing what everyone else is talking about.

Anyway, I know there is more time I have to spend at it, and I will, but I will look for a star gazing club in central Melbourne or on the coast (Lorne/Wye/Apollo etc), but it is hard for me to make time with work commitments.

Given all my reading, I decided to grab a 2" 30mm UWA GSO EP. waiting for it to arrive, but hoping it gives me a little more. Now, my questions...people talk about GSO EPs if you are on a budget (which to some degree I am) to being really good value for money, but others say they are not much better than the standard. Some of course say they are a major upgrade, all thing considered. Without having met other star gazers and without having had the chance to try other peoples EPs in my scope or to look through theirs, I was wondering on views on this point, in terms of what I think we're quite good pieces that came as standard.

Views?

Also, thinking a Barlow 2x GSO will help with my range and is good value for better seeing without breaking the bank. Trust me I've read and read but just wanted a view, worth it on standard EPs or do I wait and stay 'flat' with my current experiences?

Anyway, some questions, but more musings. Sorry to bore, just really would love to get the 'wow' factor with things like M42 (and all the other things that elude me)...looking forward to meeting some of you sometime.

Regards,

Raj

P.s. Happy Easter

[noeyedeer (Matt)]

nice adventures Raj, sounds like you'll be having lots more in the future.

I don't know if this could be the cause of the not so impressive viewing, but is the scope properly collimated? I'm sure from the reading you would've known that collapables are a lot more prone to losing collimation.

enjoy the views, I'm looking to get a dob one day too.

Matt

[wavelandscott (Scott)]

Glad you are excited and getting out under the skies.

A couple of questions...

Have you checked collimation?

Do you wear your glasses to view?

Sorry for this silly question...but do you understand how to use the focuser?

How long did you let your scope cool before viewing?

Your scope not being at a stable temperature could help account for the lack of sharp views. Same for not being quite collimated or the focus needing to be adjusted a bit.

If these suggestions don't help, it may be worth checking to see if the primary clips are too tight or if the secondary mirror is pinched in it's holder. All of these are common tweaks needed on reflecting scopes.

I don't think I would go out and start buying other eyepieces or barlows until you get the sharpness of view started.

Cheers,

Please enjoy!

[Raj (Raj)]

Morning all and thanks for the replies!

Glasses, depends on the mood I'm in, I find that the 'range' of the EPs and the scope is fine for me not to have my glasses on, much more comfortable and less light bouncing around. As for the focusser, yep have it worked out fine.

When I say things are not clear, I mean pin point. I might have set my expectations too high, that's all. I mean I've seen the rings on Saturn through the 25mm plossl that came with the scope and even clearer with the 10mm (but no Cassini division).

Its M42 that has been difficult to catch, but I admit *blush* I have not yet collimated! I'm worried I will stuff it up and at the moment I am getting what I think are decent views. I also have no collimating equipment (time and tight budget have prevented me getting).

Guess its the lack of experience and not having looked through others' scopes, I'm not sure what's can realistically expect through this Dob and these EPs.

I am going to try and get to a viewing night at Melbourne Astronomy group, or perhaps if there are people local to Melbourne/Wye River or anywhere along the South West coast that are willing to show me the sights through their scopes, or better, have a look through mine, I would be much obliged and better educated. Actually I wonderif when I go along, someone might show me the ropes of collimating and then I could get a true appreciation for the difference in visual image quality for a before/after.

Anyway, thanks for the feedback and support.

Cheers,

Raj

[noeyedeer (Matt)]

hi again Raj, found this page on cloudy nights, which backs up Scott's suggestions.

http://www.cloudynights.com/ubbarchi.../o/all/fpart/1

you need to have all the factors come together to see the CD. I'm sure last year I saw the division through my 113mm reflector but conditions were perfect, and using my cheap 21mm barlowed. I havnt had the chance to see Saturn this year (only with binos) as the weather has been a pain in se qld.

hopefully that page will help, and most defiently take your scope to an astro night, people will be keen to help you out no doubt with your concerns about the scope etc.

good luck
matt

[Raj (Raj)]

Thanks Matt and Scott,

Well I took the plunge and did my first collimation. Made my own collimating cap out of cardboard! But after about 2+ hours and in the very end with the g/f's help, got the job done. The holding clips on the primary are all visible, the secondary is dead centre in the primary and the focus target dead centre in the secondary (reflection). All tightened up and so hopefully only minor tweaks will be needed on th primary in future.

The secondary was slightly out when I started (using a white piece of paper n the opposite to the focusser, it appeared as though a slightly less than a full moon and one of the primary mirror holding clips was not visible). Wow was I scared, especially when the centre screw to the holding frame of the secondary was really tight. Thought I was going to snap something off.

Anyway, took ages, absolutely ages to get the secondary resetbut I got the confidence to understand what was happening eventually and so it was less about being freaked out at breaking something, more about patience and time.

Primary was relatively easy after the initial ordeal.

Soafter all that pain and agony, clouds Of course!

Lesson - put the Telescope on a table else you will need to find a paint tin and a cushion to get the job done! Haha.

Thanks to all the suggestions on the various threads in these forums, nks to videos etc. now just to check it out and see how much things have improved, fingers crossed.

Also, am hoping to pick up a TMB 6mm off the classifieds. Of all I have, should give me a good useful magnification with good solid optics and without breaking the bank. It was fantastic 'seeing' the other night, even without relevant experience I know that.

Oh, and yes and letting the scope cool down to outside ambient temperatures, have seen the effect of atmosphere, especially at high mag on the moon.

Anyway, will report in again soon. Thanks again for all the help and support.

Raj

[noeyedeer (Matt)]

fingers crossed its better than before. sorry for my short replies I'm on a phone and hate typing on it.

I'm quite suprised (maybe because of long weekend a d everything) that some dob owners havnt stated their experiences and what you should or could expect with a good nights viewing.

all the best and I hope that's fixed the star problem, which I think I will because the secondary was out a bit. look forward to an update when the skies clear

matt

[Raj (Raj)]

Hi Matt,

Well, someone must have been feeling sorry for me cpbeause the skies did part, albeit for only a little while. I had a crack at Saturn with the 25mm and the 10mm. Nice and clear like the other night. Not sure I could notice the difference, my g/f says it is slightly sharper. I did think I saw CD but perhaps because my mind knew the image I wanted to see. Not sure, I mean I was at 10mm which means 120x?

Anyway, at least it is certainly no worse. It may be that is was ever so slightly clearer. I did see a nice wispy Neb right up above, now just to go and figure out what it was.

Anyway, I suspect I will really only have the answers I need once someone else has a poke through my scope/EPs or I get to see through another persons same/similar setup.

Thanks again for all the encouragement.

Cheers,

Raj

[noeyedeer (Matt)]

I wish I had that luck Raj! it must've done something if your gf can see some difference .... how are the stars looking? still the same or becoming more like pinpoints?

I havnt seen saturn this year so I can't comment but if you think you did you mustve. I didn't think it was a huge ordeal to divide the rings. averted vision and a good stable sky ...

lucky b@$7ard that the skies cleared for you

[noeyedeer (Matt)]

if the stars aren't twinkling naked eye, I will get the scope out, but if they are, I won't bother, just grab the binos.
that's the easiest way to determine is seeing is good or poor ... twinkling stars or not

[barx1963 (Malcolm)]

Congrats on the scope. The Cassini Div is a little tough. I only saw it a couple of times from my backyard in my 12". It is a lot easier in my 20" but have found still need really good conditions for it to be clear. It is visible in an 8" but wait for really near perfect seeing so use a lot of patience.
Viewing at Wye Rive should be OK. You may find the seeing not as good as inland as there is always a temp differential between land and sea, but I would leave a final say on that to more experienced observers than I.
You mentioned colour. Apart from planets, stronger coloured stars and some planetary nebs, most DSOs will show no colour, they are simply too dim to activate the colour sensors in your eyes. In my old 12" I once saw a suggestion of green and pink in M42 and the green is very noticable in the 20", but with an 8" you are looking for grey!
That said there are lots of easy interesting objects well within reach of an 8" so good luck with it!

Malcolm

[Raj (Raj)]

Hi Malcolm,

Thanks for the tips, have read a number of your posts and was eventually going to get in touch to see if/when I might get a chance to meet and see if you would be willing to let me have a peek through your bigger aperture!

Anyway, for another time. With all of the advice in these forums, I am thinking more and more that I am actually seeing what I ought to be out of the equipment that I have, therefore, more time, patience and (eventually) equipment is what the doctor has ordered

I think I'm just about done with new eyepieces, simply a matter of time before they are delivered. So I will have, standard 10 and 25mm poossls, 30mm Andrews UWA 80 deg (2"), TMB Planetary II 6mm, and I am thinking a GSO Barlow to give me some variation.

I was thinking 1 more, perhaps a 17mm which, then with the Barlow would give me a lot of range. A GSO is what I had in mind (budget conscious). Any thoughts or or views on my thinking?

Cheers,

Raj

[barx1963 (Malcolm)]

Raj
I am not a big fan of barlows for the simple reason that in my opinion a good EP is always better than a good EP and a barlow. The EP has been designed to give good views by itself, and logically there is no way a designer can make a barlow that will match up a range of fls in someone EP collection. Also more glass is never a good thing. I have used both Barlows and Powermates, only Televue, and never been happy. Views always seem a bit mushy compared to using a good EP.
The only argument I can think of is that it gives more power without sacrificing eye relief, but I think there is better value in quality EPs.

I may be going up to Snake Valley for the club night on April 12. Will let you know if that is happening.

Malcolm

[raymo]

I have to disagree with Raj concerning barlow lenses.Firstly, "more glass is never a good thing" only applies to the fact that we want all the light we can get, hence most astro scopes invert the image because designers
omit an erecting lens. Regarding optical quality, more glass has no
detrimental effect whatever. This is shown by the fact that good quality
camera lenses will always produce better images with fewer aberrations
than any lens/ mirror/ eyepiece combination, and that includes APO
scopes. The reason for this is that camera lenses contain many
elements in several groups; each group being designed to minimise
a particular aberration. Typically a lens will contain 8-12 pieces of glass.
Barlows don't have to match up to any particular F/L eyepieces.
The eyepiece being used is irrelevant; All the barlow does is cause the light passing through it to diverge and typically doubles or triples the
F/L of the scope. Through a decent quality barlow there will be a
slight loss of quality, but the reason is that you have doubled the magnification, and a 6mm eyepiece will not give the same quality
viewing as a 12mm. As you will be aware, as magnification increases,
image quality deteriorates. So, optically there is not much to choose,
but practically why would I jam my eye up against the tiny lens of
a very short F/L eyepiece when I can view more comfortably through
a medium or long one. Incidentally a barlow does not magnify
without sacrificing eye relief; it actually increases the eye relief of
any eyepiece used with it. A final benefit is the fact that the longer the
F/L of a scope, the less obvious any aberrations in it's optical train
become, which is why scopes many years ago had enormous focal
lengths, such as the Yerkes 40" refractor which is an f/19 scope.
There is also the fact that even if there was a small loss of
image quality, unless you are loaded, and money doesn't matter, it would surely be acceptable in order to effectively double your eyepiece
collection.
raymo.

[barx1963 (Malcolm)]

Fair enough Raymo. The point I was trying to make is that each piece of glass reduces the overall light transmission slightly, it may only be slight but every photon is precious!
Apart from that I was relaying my own experience using good quality barlows. The image was always superior if I used a stand alone EP giving the same power. I had a 24mm Pan and if I barlowed that the image was noticeably more "mushy" than I had with a 13mm Nag. I know the powers are not exact but close enough. Same went for barlowing the 13mm nag against a stand alone 7mm nag.
If I was restricted to using plossls with horrid eye relief and tiny exit pupils at high powers, then yes a barlow can make sense, but stand alone EPs have worked when talking better quality EPs.

Malcolm

[raymo]

Also fair enough Raj. I don't know if you are into imaging, but if so,
noticing that you have, like me, a fairly fast scope, try getting the
magnification you want by using a barlow with an eyepiece, and then compare the result with an image obtained using just the eyepiece that gives the same magnification on it's own. Unless you already have a coma corrector, you should see less coma in the barlowed image.
I just remembered that your camera gear is listed here, so, of course you are into imaging.
regards raymo

[raymo]

Oops!! I meant Malcolm, not Raj.
raymo

[Raj (Raj)]

Hey guys,

Thanks for the further info and differing views. Once I get the 6mm TMB Planetary II it might be that I don't need a barlow so much, BUT I did get my Andrews 30mm 2" 80deg last night (unfortunately the Dob is not with me) so when I get my goggles onto that, it might be that want some zoomage on that nice bit of kit (can't wait to look through it for the first time)!

Anyway, any comments about the quality of standard 10 and 25mm plossls that come with Saxon dons? My eyes tell me these are not too bad, but I am sure the TMB will add a big pain to my hip pocket as I will want lots more new lenses of high quality, right??

Thanks again

Raj

[Paddy (Patrick)]

Whilst good eyepieces make a difference, at this stage of your observing the main thing will to adjust your expectations and observing practices. With Saturn for example you will as Malcolm said, see the Cassini division in good conditions - steady seeing and when the planet is high in the sky. Probably after 2 am at present on a good night. You can only ramp up the magnification on nights when the seeing is excellent.

For deep sky objects, remember to use averted vision as the rod cells necessary for low light viewing are not situated at the fovea, the point on your retina where the image falls when you look directly at something. Most nebulae will look at first like milky smudges. As you keep exploring them you will see more an more detail - dark lanes, patches of brightness, small clusters of stars etc. Keep coming back to objects in different sessions and you will see more. Even better, get a red light headlamp (not too bright) and make notes or sketches and you will see even more as you become systematic and hone your observing skills. This thread may help you. Patience and understanding night vision are the key.

Hope this helps.

[barx1963 (Malcolm)]

No Raymo I am not an imager, I have camera gear but only use it for terrestrial ATM. The "dark side" hasn't got me yet!!
My comments are based largely on what I see in the eyepiece, and I am primarily interested in how the object I am viewing presents. In my experience, I have found barlows not helpful. For imaging I can see they have their place, but personally I don't care if there is a bit of coma at the edge of the field, one reason I use Ethoi, any coma is "way over there" at the edge!!

Raj
I have had 2 sets of Saxon/SW plossls (25 and 10mm ones) with scopes I have used and have commented on them several times. I also hads a set of plossls (32,25,15,12,9 and 6mm) that came with my GSO 12" dob, so I have a fair handle how they work and compare to premium EPs.
Of the 2 Saxon/SW ones, the 25mm is not a bad little EP and should be the one that spends the most time in your focuser. Eye relief is adequate, gives a reasonably flat field and sky background was nice and dark. The 10mm is another matter. Eye relief is short and the exit pupil is tiny so you have to really concentrate to hold an object in the FOV. It also has a tiny focus range so you need a really gentle touch to tweak the focus. I still have my 10mm plossl. Every now and then I pop it in to remind myself how good the new EPs are!
With the GSO plossls, it was much the same story, the 25mm was acceptable, 15mm just useable and the others rarely came out. The 32mm was not bad but coma was really noticeable.
We are fortunate that we live in an age where some excellent EPs are available. IMHO premium EPs are a great investment for any visual observer. The views that can be obtained with Ethos and Nagler EPs have to be seen to be believed.

Malcolm

PS some good advice from Paddy. Observing is not just looking, keep going back to objects and you train your eye and brain to see more!!