Help me calibrate my expectations

[DaveS]

Coming back into the hobby and finding a lot has changed, I need some calibration marks!

Back in the day, the usual amateur instrument was the home-made 8" f/8 Newtonian. So what should I be looking for now....I won't be buying for some time, possibly a year with the economy and all, and my back garden is too restrictive for an obsevatory. I'm thinking of a small-ish (<4") apo for imaging, but light pollution in west London will limit what I can do, also looking at my sky view, I see two sites within the garden, one near the house has a good view of the polar region, but the south is obstructed by trees, while the far end has a reasonable view of the south, but the polar region is obstructed.

I'm thinking therefore of sinking three concrete footings in the ground at each site to take a tripod which I'll keep indoors.

So...what is a reasonable eq mount on a tripod for portability, and what could I reasonably expect to mount on it?

I know I've still a lot of research to do, but if someone can say what's do-able in their experiance, that would help greatly.

If you've got this far through my rambling post, thanks for your patiance

Dave

[ChrisEdu]

Could you not just 'adapt' the trees to improve the view?

[adamsp123]

Much will depend on your final budget, look at second hand market soom good bargains to be had.

[Bigwings]

I have similar obstruction problems and I wanted something to take out to other sites from time to time.

I settled for a Celestron Nextar SE8 as the largest scope I could move around whilst having a good size apeture. Its Ok with my piggyback camera and my nextar Imaging setup but the purists will tell you that the single sided mount is not best suited to imaging.

The GOTO is acurate and good .

You dont say what you want to spend?

[DaveS]

The trees to the south are two houses away unfortunatly . Two of the trees to the north are in my garden, one is a golden fastigiate Yew, which may be amenable to pruning, the other is a Thuja, so I don't know. I don't want to ruin the shapes. They've grow up since I put my hobby on hold 20+ years ago. I should mention thet there is a 6' high fence to the south (My neighbour's) which does shield the site from too much LP from houses to the south, but rules out Dobs. There are no street lights in view, and the local ones are "good".

Budget...what it takes within reason, up to say £1500 for the OTA and 650-850 for the mounting, but I don't want to go mad on it. Does that seem reasonable?

My "local" 'scope shop would be "The Widescreen Centre" any good?

Dave

[jgs001]

Dave, give Steve @ FLO (see linky at the top of each page) a call. You should be able to get some stonking kit with that sort of money.

[DaveS]

I probably will at some point, I've been on their web-site rather a lot of late however, since I'm not buying for a while yet, I don't want waste his valuable time. When (If) I'm closer to buying I'll give him a bell.

What sort of scale of instrument would be portable enough for what I'm planning, I need to keep my goals realistic, as I know I'm quite capable of catching Aperture Fever

Dave

[adamsp123]

New SW 120ED (or 100) pro refractor on a HEQ5 PRO mount or EQ6 (heavier) both with goto and mony left over for accessories which will cost a fair bit......EPs guidescope for AP etc

[MartinB]

Hi Dave, if your LP is bad then your deep sky views are going to be disappointing regardless of aperture. You could improve things with LP filters but you are still going to be compromised. The solar system is another matter and much less effected by LP.

Although aperture will potentially improve your resolution you need very good seeing to benefit greatly from going beyond 5" On most nights I prefer lunar and planetary views through my ED120 than I do through my 10" SCT and 12" dob. The enhanced contrast through the ED120 makes features stand out more clearly. An SCT would be great for high power solar system imaging in good seeing. Alternatively an decent maksutov could be just the ticket if you want to fully commit to solar system.

If you did decide to major on solar system observing/imaging then a good view of the ecliptic is the key thing, a good southerly view would be tops.

An ED120/equinox or an 8" SCT on an HEQ5 would seem like a good bet. Both will also perform well on DSOs - the ED120 gives lovely views of open and globular clusters which would show through your LP.

[DaveS]

Thanks This confirms what I've been thinking, under 5" (Sorry I'm old school ) under f/8 refractor on a good though not heavy mount...I think!

LP in not good, but not, I think a killer, I remember getting good views of Orion, The Crab and The Ring neb in Lyra with my old 8" newt.

Anyone in the Acton / Ealing-ish area of London care to comment re: LP?

I've aready assumed the need for LP or even narrow band filters for both AP and Vis. I'm taking this slowly, one step at a time since I don't want to go throwing money around to no good purpose.

Dave

[roundycat]

many people would say that with the budget you outlined above you should look to spend £1500 on the mount and £650-850 on the scope.

Dennis

[MartinB]

many people would say that with the budget you outlined above you should look to spend £1500 on the mount and £650-850 on the scope.

Dennis

Yes, if you are looking at DSO imaging it is all a bit different!

[thing]

I would agree with Adam, my scope and mount cost around £950, I've easily spent that again in eyepieces, filters and the other junk that you need.

[lunator]

Dave

I live close to Richmond, so not a million mies from you.

For deep sky visual you will be mostly limited to the brighter nebulae and clusters.

There are only a few nights (about 3 per year) when the sky is clear enough to see faint galaxies.

I chose to observe double stars as they are generally visible if it is clear.

I am a member of Richmond & Kew Astro Soc. Our next meeting is a visit to ROG. If you are interested incoming drop me a PM.

Rgds

Ian

[Whippy]

IMO, I think it may be better to buy a scope on a good EQ mount for now, buy a couple of eyepieces and get back into the swing of things by observing. then, when you feel confident with the mount go for the imaging kit.

Tony..

[ngc2403]

You are clearly a skilled guy to have made your own 8'' newt and seen the crab, etc through it!

i would say that your current slow steady approach is the way to go.

apon starting up for the first time i went from, i need an; apo to focal length to aperture to focal ratio to contrast in about a year. i takes time to get the right scope don't jump in.

with your budget you could get a good setup for anything you like DSO, planets, the moon, visual or astrophotographs

good luck with the research ally

[Tim]

I have an idea!

What about popping along to one of the star parties, maybe even, no, ESPECIALLY even, the SGL one in April. There you will be welcome to see the various setups, have a gawp through the visual stuff, and watch the imaging crowd cursing their kit all night.... You would be made most welcome, and I for one would be happy to demonstrate a 'typical' imaging setup, and explain why you need about 900 miles of cable etc etc.

For when you say "imaging", how do you mean? For there is "imaging", and then there is "imaging". I remember asking almost the same question as you just over a year ago, with a similar budget. It turns out that there is a little more to it then just plonking your kodak on the end of the telescope and clicking away. What type of photography is of interest to you?

My skies are badly affected by light pollution in every direction, and it is very rare that faint stuff is visible, which is one reason why I take long exposure photographs with a light pollution filter in place. It's a workaround, and yields reasonable results. At the moment I am using an 8" F4 newt for that, but have also at hand a C9.25, 72mm 'normal' telescope (forgot proper name sorry), a 6" F4 newt, and 12" dob. They will all probably be making the trip to Lucksall in april, and you are welcome to come and see. I'm sure that goes for the others too. If you have a year to make your mind up, thats a luxury that will help you make the right decision from the start, rather than waste money on kit that doesnt really cut it for you.

Hope that helps a bit.

TJ

[Astro_Baby]

I remember when a long tube 8" Newtonian was king of the hill as well - with a price tag to match.

Its amazing these days that incredible optics are available on equally amazing mounts and really quite cheap - even with the price hikes.

I remember looking through the window of some shop in London with may face pressed up to the glass and dreaming of one day owning a big telescope - I had to wait a bit longer than I had thought

[DaveS]

Thanks to all, and sorry for not getting back earlier! I've been bashing my head against a recalcitrant camera tracking mount that I've been trying to get to work, I think I'll scrap most of it apart from the PA and start again from first principles....bother or words to that effect!

The pointers about the budget are something to think about, and I'll have to be more modest in my aspirations, ie a doublet rather than a triplet refractor...again bother ...I really wanted a WO or Tak 132 .

So, my plan of campaign....get my tracking mount up and running, and start basic imaging with my DSLR (Canon 5D) and various lenses, 135, maybe a 300 f/4, and a 2x extender, while considering a modded Canon 450D and clip in filters.

Meanwhile investigate my observing positions, put in some kind of foundations or even a fixed pier concreted into the ground to take a decent eq mount (I wouldn't consider anything else).

Investigate a modest refractor that I can use visually, as well as for imaging, (I've read that even ED doublets show considerable secondary spectrum at the f-ratios for imaging, what do you find in practice?), possibly 120mm (See, I can use metric!).

assuming I even get that far before LP and cloud depress me into giving up again, I hope not!

Again , cheers to all,

Dave

[adamsp123]

Dave, if you have any doubts about imaging with a doublet have a look at this short movie and also look at some of the other photos coming from these "not so good doublets".

http://www.andysshotglass.com/120ed_2.html

Pete

[Whippy]

Dave, it's been an ongoing argument in refractor circles that just because it's a triplet it doesn't make it good. Many people would say a well made doublet would 'beat' a poor triplet because it's how the glass is put together rather than how many there are . Have a look at the imaging boards here and you'll see loads of great images taken with a £200 80mm ED doublet scope.

If you're talking about money that involes a 5" apochromat, why not look into a cooled CCD astro imaging camera? You may find that your light pollution may restrict you to narrowband imaging in which case a) a monochrome camera would be ideal and you won't have any potential issues with colour in your prospective scope purchase.

Tony..

[DaveS]

Good people, many many thanks for all your replies .

I guess I've got to re-learn how to walk before I can run , but the advice I've been given here is exactly what I've needed!

One more short question then I'll be done,.. should I expect to make scientificly valid observations with a small 'scope, from a light-polluted location because all I can think of are variable star measurments, which I have no confidence in my ability to make. I'm thinking double-star work needs a bigger refractor and a good eyepiece micrometer, and my local seeing is a bit duff for planetary work. Lunar may be do-able, I don't know, will think about it, while DSO needs (I think) a bigger'scope and a dark location.

Sorry to sound negative, I'm just trying to be realistic.

Dave

[roundycat]

Dave, have a quick butcher's here http://www.dens-astropics.org.uk/page%202.htm most of the pictures taken with the G11 mount were taken from Hornchurch which is pretty badly light polluted. You will also see many pictures taken with the WO ZS80FD, an 80mm doublet. In general I would say that your technique needs to be OK before you begin to see faults in the scope unless it really is a piece of rubbish.

Dennis

[DaveS]

Thanks for that link, It's given me something to think about, and confidence not to go chasing aperture or fancy optics......for now

Dave