Choosing OTA for DSLR imaging

[AndyUK]

Hi there... Although I know I'm almost certainly trying to sprint before I can crawl, I'm trying to think ahead so that I don't spend too much money trying to make what I have perform okay when I could save up and spend more to achieve what I REALLY want to do well.

Although very happy with the viewing performance of the 102 refractor and 130pm reflector both on an AZ goto mount, I definitely want to take photos. I have a Toucam 840k (which I know I still need to experiment with), but it's looking more and more likely that getting my 300D to work well at prime focus on my current kit won't really work.

I've been advised by FLO that the 130 focusing mount really won't take the off-axis weight and attaching the DSLR to the 102 on the AZ mount would require me to buy some additional rings and another dovetail - Although not much in the grand scale of things, as I'm using an AZ, the max single exposures I can get anyway will be c. 30s and hence I'm having to think again...

The first is a no-brainer - I need to budget for an EQ mount. I know they're pretty heavy, but for my purposes I think I need an EQ5 (or higher).

The next thing is the OTA itself - Again, although fairly happy with what I have (especially as a grab & go scope), as the refractor is achromatic, to get the type of pictures I want I could buy a fringe killer but I think I'm really going to need to look at an APO. I've done a little research and come up with a short list which I reckon will be within budget:

1. Sky-Watcher Equinox 80 ED APO (500 / 6.25)

2. Sky-Watcher Evostar 80 ED DS-PRO APO (600 / 7.5)

3. William Optics 80 Zenithstar II ED APO (545 / 6.8)

4. Meade 5000 80 ED APO Triplet (480 / 6)

5. Sky-Watcher Evostar 100 ED PRO APO (900 / 7.5)

6. Sky-Watcher Evostar 100 ED DS PRO APO (900 / 9)

I'm sure that these are all good scopes, but I have a feeling that the Meade triplet possibly has the best optics and will probably give the best resolution(?), but the focal length appears fairly short, whereas the Evostar 100 DS (with its wider aperture and almost double focal length) may be more effective at DSO's?

Has anyone got any comments that might help me decide...?

[Mick UK]

Andy, you wont go far wrong with the Sky-Watcher Evostar 80 ED DS-PRO as im certain plenty on here will testify to.

I had this same dilema a while back and a lot of people advised me to Get the 80ED PRO and also the Skywatcher EQ6 pro mount.

I could'nt really afford them both at the time so i bought the scope to play with on an old eq3 mount i had, untill i got the funds to buy the EQ6 PRO....Best advice ive ever had...i love this setup, you'll be amazed at the quality of the DSO's, and then in the future if like me, you decide you want a bigger scope (ive just bought the 10" Skywatcher 250, mainly for visual) you already have the mount in the EQ6.

Also with the price of the 80ED PRO you'll have some change for any bits and pieces you need such as T-mount etc.

Im sure the good people on here will give you more detailed advice on the other scopes on your list, but for value for money, i'd take the 80ed pro/eq6 pro any day:)

[AndyUK]

Cheers Mick - I did briefly look at the EQ6 PRO (and also the HEQ6 PRO) but thought they might be too heavy for me to cart about.

I live on an estate where sodium lights abound - There's 4 directly visible from my back garden and the closest is literally just 30 yds away due south. East is mostly blocked by the house and low west by trees so I only really have about (at best) 1/4 of the sky available to me at home

So I need it to be relatively portable to drive away to my "dark" site a couple of miles away. I know I could probably pop along to my local astro shop to get an idea of the actual weight / awkwardness, but can I ask if you move yours about much...?

I do love the idea of keeping options for a 10" reflector open later (and I can't begin to imagine what you can see through it!), but I think to get most use out of an EQ6/HEQ5, I'd really need to move more into the country or shoot all the streetlights out.

[samtheeagle]

I've recently picked up an HEQ5 mount, and although it is a massive lump of metal I have no real trouble lugging it downstairs, out to the car... Then unload it, clamber over a gate with it in hand etc. That's not to say that I don't have a bit of a sweat on by the end of it! But so long as you're not suffering some kind of ailment you should be fine moving it around.

It's swings and roundabouts I suppose. I know that I haven't got the best load capacity, but it is still a very substantial mount, but not too much to move from place to place. Like you said, it'll be good for you to go to a shop to try lifting some of these beasties up to see what you're letting yourself in for

[ollypenrice]

Of the telescopes you mention I would go for the ED80s, either the Equinox or Evostar. They do come under a variety of brands and variations. The one of which I have seen the most is the basic old gold coloured Evostar. Used for imaging the results are quite extraordinary. I daresay the faster version is even better, I don't know. (The 2 speed focus is a bonus for maging but you can attach a protruding lever or 'wand' to the single speed for finer control.) You would need to budget for a flattener-reducer for the ED80 if using a DSLR because of the generous chip size. This is one of those happy areas in which the cheapest may well be the best!

I have a couple of EQ sixes doing good work down here but I don't have to hump them around. The HEQ5 Pro would be more than adequate for an 80mm and much easier to maoeuvre. It is less future-proofed in terms of carrying larger scopes later but there are SO many targets for a focal length of around 500 mm that only in Galaxy Season will you start to feel frustrated any time soon. Anyway, when starting to image you want a short focal length and fast f ratio which will make fewer demands on your tracking accuracy. Keep it fast and short.

Although Nadeem may disagree (he does wonders unguided) I would suggest that you start to think 'autoguider' at the earliest stage possible. Really. There are some inexpensive ones around now and any old clunker of a guidescope will get you started.

Oh, and get a Bahtinov mask. It is the only sane way to focus a DSLR. Looking at stellar images to do so is like trying to guess what a barcode says...

Olly.

[adamsp123]

In your situation where you need a relatively portable system I would go for a 80ED scope, and a secondhand Vixen sphinx mount, new they are too expensive IMO, but they are soooo light, I will be imaging using my S/H sphinx with a 120ED on top at SGL5, the HAL aluminium tripod if left in lowest position is remarkably stable. With a 120ED I only need the small half size counterweight to balance it keeping the loading on the mount to a minimum. I also go along with autoguiding idea, try a finderguider, again lightweight and swap with finder once target is acquired and no need for extra bits and bobs to hold a guidescope (weight).

If your situation changes and portability is not an issue then EQ6 is a good bet.

My 2ps worth

Pete

PS if you are going to SGL5 or popping in I am happy to let you have try out of the mount.

[AndyUK]

Cheers all - The general consensus here is pretty unanimous - 80ED!

I'll see if I can "escape" for an hour this afternoon and go and do a bit of weight lifting of the EQ5, HEQ5 and EQ6 Pro mounts - If as I suspect the EQ6 is a bit much (24kg), maybe the HEQ5 (16Kg) will be manageable (and at least it would afford me the option to mount a 200 reflector later if I wanted to). I was originally budgetting for around £1k, but I'm pretty sure I can justify the extra £250.

Olly - Thanks also for additional info... it's very useful to know of "the extra bits" needed to get really good results. I've seen flatteners mentioned (and understand the principle), but didn't really know of the necessity (also very glad for advice that I don't need to spend the earth on these - I see they range from £65-£225!). I've seen Bahtinov masks advertised too, but again had no real idea how they work or of their importance (but again, thankfully not too expensive)

However, I need to do a LOT more research into auto-guiding... It's something I've thought about, but then ignored (as I only currently have an AZ and it hasn't been worth concerning myself with!)

Pete - Vixen mounts... VERY nice indeed, but I certainly couldn't push to one of those new, and I strongly suspect that second hand they're pretty scarce (and sought after!). However, I'll certainly keep an eye out over the next few weeks / months - That would be a panacaea!

I love the idea of the "finderguider" but I'm not sure I undertand how it works (and couldn't find one on Google?). I assumed that auto-guiding required another scope mounted on top of the main one to which a video cam is attached and then, via software, you can "lock on" to a star/object which then feeds corrections back from the laptop to the mount... Or have I totally misunderstood?! (Sorry to be naive / obtuse!)

However, as I noted above, I haven't looked into this at all to date, so I think I'll have to consider that as another (separate) project - The budget's beginning to stretch a bit too much for a one-off purchase - I thought I'd done well to get authorisation from my wife for £1k!

Thanks also for the offer of having a look at your set-up at SGL5 - Unfortunately it clashes with my birthday at the weekend on top of which I'm working in Zurich at the beginning of that week - I don't think my wife would understand if I went away on a jolly as soon as I got back, but I hope the weather stays good and the skies are clear for you all...

[Keiran]

HI ALL,

I AM A NEWBIE, TO BOTH THIS FORUM AND TO ASTRONOMY I HAVE RECENTLY PURCHASED A SKYWATCHER EXPLORER 200P.

I AM REALLY HAPPY WITH IT HAVE MANAGED TO USE ONCE, WEATHER HAS BEEN TERRIBLE, LOL.

I HAVE GOT A SONY A100 AND HAVE NOW DECIDED TO TRY AND TAKE SOME PHOTOS WITH THIS.

THE PROBLEM THAT I HAVE, IS THAT I DO NOT HAVE A MOTORISED TRIPOD, I HAVE A EQ5 FOR REF.

NOW, I CAN NOT DECIDE WHETHER OR NOT TO BUY A RA MOTOR DRIVE OR A SYNSCAN GOTO?

TH RA DRIVE IS AROUND £100 BUT LIMITED USE AND THE GOTO AROUND £300, CAN ANY OF YOU GIVE ME ADVICE PLEASE.

THANKS ALL ONCE AGAIN KEIRAN.

[adamsp123]

Andy,

Some info,

Finder guider -

http://stargazerslounge.com/diy-astronomer/84726-diy-finder-guider.html

S/H Sphinx here -

U.K. Astronomy Buy & Sell

[Mick UK]

Andy, if your reasonably strong, the EQ6 would'nt be a problem for you, especially if you take the weights off as well as the scope to move it.

Dont get me wrong here, but ive been bodybuilding for around 25 years so i guess im a lot stronger than most on here, but i pick the EQ6 up with 3 weights and my new 10" reflector and move it around the garden, as im also restricted in the amount of sky i can view from my position where i need to see polaris to do my allignment.

I also had some street lights glaring into my garden as well, what i did, was to get a very long pole, attach a paint roller to in, dipped it into some "silver" metal paint (i chose silver because it looks like glass in the daylight on the lamps!) and i painted a portion of each light at 3am!! i only painted the part of the light which shone into my garden so no one knows any difference and i also put some ply board on my fences between me and the lights.

My back garden is now in complete darkness!

ps...get a 2" skywatcher light pollution filter (i got mine from first light optics excellent srevice) they really do work for imaging if the lights around you are the yellow sodium type:)

[AndyUK]

Hi Mick - Totally love your light pollution solution . It reminds me of when I was 14 when I shot out a mercury street light with an air rifle. I spent ages getting the telescopic sights perfect and I was extremely proud of myself when I took the element out with a single shot... The only problem was that the shot could only have come from one place, and a few days later we were visited by the men in blue and I spent a very uncomfortable hour down at the police station. Looking back, the penalty was pretty lenient (I had to pay £38 damages), but it certainly taught me not to use street lights as target practice!

I did go weight lifting yesterday... The EQ6 is a bit of beast, isn't it!? I think my decision is going to be whether I'm happy to limit my future upgrade path to a 200 reflector (or 150 Mak) on the EQ5 or whether I can stretch the budget to allow a 250 on an HEQ5...

(NOTE: I think the EQ5 MIGHT be able to stretch to a 180 Mak as well. The specs say its max payload is 9kg, and a Mak 180 is about 7.8kg - It's possibly a bit tight though with a DSLR and a focusguider on it...)

Thanks also for advice re: Skywatcher LPR - I currently use a Lumicron UHC which does a really good job, but it's only a 1.25"... Ho hum...

[tooth_dr]

I can just add that the EQ6 mount (without tripod etc, weighs) about 16-17kg - not heavy. BUT it comes down to awkwardness with three legs making moving tricky. An EQ6 with 1 c/w and an ED80 - easy to lift around - and a super solid setup. But not imo a portable setup despite it not being physically heavy. The EQ6 is overkill for a portable setup with an EQ80.

[AndyUK]

Cheers for that... I do agree. The EQ6 mount in itself isn't actually that heavy (16kg), and I personally didn't really notice that much difference between the HEQ5 and EQ5 mounts (my dog actually weighs more than the EQ6 and he's certainly more awkard to carry!). But I did find the extra 6Kg of the EQ6 certainly very evident when placed against the EQ5 (when picked up side-by-side) and I certainly couldn't carry ANY of them very easily fully set up, but as it wouldn't fit in the car fully set up anyway, that's not an issue - For me, it will probably take 3 trips to/from the car regardless of which of these mounts I choose...

Bearing in mind my budget though, I have to consider whether I want to have the option of being able to buy a 250+ reflector later without having to buy a new mount vs the additional cost of c. £250 for the HEQ5 or c. £420 for the EQ6 (now where's my crystal ball..?)

The responses to this post have REALLY helped my decision process - I have my shopping list - Thanks all!

[Astro_Baby]

I have the HEQ5 and recently worked on an EQ6 for someone else. In a shop ages ago I felt the weight of an HEQ5 compared to an EQ6 (unloaded with no weights or scope) and concluded there really wasnt much in it.

A weekend of tuning an EQ6 and having to drag it around the flat at times has convinced me otherwise. I can just about totter with an HEQ5 fully loaded with a 200 scope on it. The EQ6 even with one weight less and a lighter scope (ED180) was damn near impossible. The extra bulk alone is a killer plus its legs are heavier as well.

It may not be THAT much heavier on paper but theres always the straw that breaks the camels back.

You also have to think, depending on where you live, what the impact of additional weight will be. I can lug an HEQ5 around quite easily in an open field. In the closed confines of a flat it gets harder, taking it down 6 flights of stairs without bashing the bannisters or the mount harder still (and taking it back up them is no fun either at 3am when you have been on your feet for 4 hours in the cold).

If the weight goes up then the chances are you end up making one more trip up and down stairs. For me its a 3-4 trips to get all the kit. An EQ6 would push it to 5 trips. It doesnt seem much as a one off - do it 2 or three times and lug it back up 6 flights of stairs after abortive sessions when its been cloudy and your opinion will more than likley change.

Make sure you consider all those factors in the mount. What you can lug out to a car from a shop is quite different to what you can lug over a fence in the dark and the difference will be between a scope and mount you'll use and one which you wont.

[tooth_dr]

^^^ great advice there.

[AndyUK]

That was exactly my thought process...

I'm also a (fair-weather) angler and go fishing at a local 3 lake complex - The furthest lake is by far the best, but very few people get to it as carrying the kit all that way is such a nightmare. I've made it 3 or 4 times and had some VERY good days there, but even then, when it comes to packing up, it rather clouds the day having to drag the kit all the way back... So I don't go there that often.

Astronomy for me is a relatively new hobby but I'm amazed at what's out there and how much there is to learn... Which I really want to do. However, I do want to enjoy it and not feel that any part of it's a chore - I have a day job to supply me with that!

I'm therefore going for an ED80 (Equinox or Evostar) and an EQ5 Pro Synscan which I reckon should keep me well occupied for a few years. And if I've got my sums right, I'll only go slightly over budget buying a flattener, a polar scope, a Bahtinov mask, guiding software and making a finder guider (oh, and of course getting a balaclava, a long pole, a paint roller and some silver paint!)