Minimum Mount to get anything? (DSO)

[t0ny]

Hi, 

I got a telescope a while back and a second child soon after. Unfortunately my daughter had to take preference and the Telescope got boxed in the loft. I have recently moved to a bigger house where the nights are black (Norfolk, UK) and I also have a pretty big man shed too. To my delight I found my telescope when moving and I have even managed to set it up.

The scope is an SW150p on an EQ3-2 (with dual axis drive). Also in the box I have one of them bahtinov masks, a modded web cam, small laptop and an old Nikon D80 with a collection of lenses (biggest is 200mm).  

When I tried this before I could not focus using the mask and my Orion Nebula was blurry, although you would not have thought it when I ran into the living room showing my unimpressed wife the pink splodge. 

Now I know from when I got this many years back i was told the mount in particular was no good for AstroPhotography (DSO) and that I must sort that first before attempting anything.  Is this definitely true? Is M42 not obtainable with what I have? (You won't hurt my feelings too much).

Does everything need replacing? If that's the case I'm screwed. I'd rather keep the scope for now, but I don't really know if it is ANY good for this?

Thanks,
Tony

[DaveS]

OK

Looking at what you've got I'd say the inevitable HEQ5 Syntrek would be the minimum to go with. the reason it gets so many recommendations is that it just plain WORKS. It's now a mature mount with most of the kinks ironed out and is well supported with software. As you already have a laptop you can download Cartes du Ciel and EQMod (Both free) to control it. You'll also need a guider with that 'scope, try a Skywatcher ST80 and add a guide cam of your choice.

Your EQ 3-2 isn't a write off by any means, as you can mount your Nikon on it with a prime lens and get reasonably well tracked wide-field shots.

You should also look into software to process your photos, Deep Sky Stacker is free, but beyond that you'll have to pay.

[ronin]

The mount is a bit too light for the scope. What will likely happen is that you end up throwing a lot of the images away as they cannot be used. However that means some will be usable.

Say that with the EQ3-2 you throw 2/3 away but with an EQ5 you only throw 1/3, that will be the sort of thing --- both values are simply expamples to get the idea.

The scope is not intended for imaging with a DSLR, the docuser cannot get the camera(sensor) in close enough to get a good sharp focus. That is likely why the mask did not work previously.

To sort that out you need to move the mirror up the tube a bit so that the focal plane gets pushed out and you can get the image on the sensor.

Wives do tend to be unimpressed by pink splodges, no idea why but they are strange creatures after all. I guess replacement is not an option as it tends to be messy and costly and no guarantee the replacement will appreciate pink splodges any more. Stick with what you are used to.

Are you part of the Norwich Astro mob?

Sounds a reasonable group, meet at some dark place (Toadds Lane ? sort of SE of Norwich).

Thinking someone there may be able to give direct advice and say how to move the mirror up.

After that set scope up as best you can on the mount and try a few images of short exposures say 30 seconds or 60 if it all goes well.

It is one of those things, an EQ5 would be better, an HEQ5 better still, a 130PDS is set to attach a camera to and an apo likely better still. But you have the EQ3-2 and the 130P so work at it as best you can. You will learn a hell of a lot more.

[t0ny]

Oh dear, bad tidings indeed.

I might join the queue hunting for a second-hand HEQ5 then. Are they upgradeable to a Synscan setup later on?

That's a big shame the scope is no good. What sort of scope should I look for for DSO? Hopefully that's not like saying what car should I get for the road!

Wouild you sell this stuff and start again, or could this scope complement a basic DSO setup? Ideally I'd have one for both, but I bet its not that simple.

I'm not part of any mob yet ronin, I only saw the Andromeda galaxy for the first time the other night!!! Massive beginner with typical unrealistic expectations.

Thanks for your advice!

[carastro]

You could probably mount your scope on an HEQ5 depending on the mounting hardware and use it for visual.  A basic scope for DSO is normally a small refractor, but get an APO otherwise you'll get chromatic abberation.  The one generally recommended is an ED80, but there are a few others out there too.  

Carole 

[DaveS]

A HEQ5 pro is upgradeable to synscan from Syntrek, but with a laptop running Caretes du Ciel and EQMod you won't have to, as the combination is cheaper and better

Also, if you're imaging with a DSLR you'll need a fast 'scope especially with an older model like the D80, so the "classic" ED80 at f/7.5 might be a bit slow. It might be worth looking at that other beginning imager's favorite, the 130 PDS. It's significantly faster at f/5 and designed for imaging, so you'll be able to reach focus with a DSLR. You will need a good coma correcter and a collimating tool.

[t0ny]

Hmm OK. Syntrek is my target then!

So a 130PDS would be better than my 150P because it has a shorter tube and this is better for focusing and faster?

Would a 150PDS be better again just because its a bigger reflector?

Would my 150P be better at anything or would a PDS be all round better?

[DaveS]

I'm not sure about "better" but the 130 PDS should be easier to get going with and will put fewer demands on the mount and guiding, which you will need to sort out, as you'll need to take longer exposures with your D80. The main difference as far as the 150 and 130 PDS will be in image scale.

Your 150 P would be better for visual, so might be worth hanging on to.

[Chris]

I've seen people ask about DSO astrophotography with a lot worse kit than you currently have! You have a fast f/5 reflector and a motor driven EQ mount, so good start You should reliably get 30 second exposures with this setup which will be enough to practice with. Use a reasonably high ISO say 1600 and stack a load of exposures in Deep Sky Stacker to increase the signal and reduce the noise.

I think its worth playing with what you have whilst saving for a better mount for sure, many of us started with EQ3's and EQ5's

There is one worry I do have which is you mentioning that you cannot get focus even with a focus mask? I've imaged with the 150p and the latest black tube models do reach focus with a DSLR but I know the old blue tube models don't

If you have a black tube 150p keep it and stick it on a better mount when you can affored to. If you have the blue tube model sell it and get a 130pds The 130pds is cheap, as a better focuser, larger secondary for better field illumination, its lighter and less of a wind sail, and the focal length is slightly shorter so it will show tracking errors to a lesser extent. 

Bigger is better for visual but not for imaging, I image with a scope that has 66mm aperture

[DaveS]

At the risk of boring everyone with a suggestion they've all seen before, if you don't already have it, get a copy of "making Every Photon Count" by our own Steve Richards steppenwolf of this forum, available from our sponsors, FLO. See banner at top of page. Read it twice before spending any money.

[t0ny]

Ah thank you so much Starfox, that's great to hear!

I do have a black 150p so perhaps I need to spend a bit of time learning how to use the mask. The Sky is much darker where I live now so that must help when you're a beginner like me!

Plan looks to be to get an HEQ5 Syntrek with laptop linked up rather than Synscan (When funds allow)

I take it for 30 second exposures I don't need all this guiding stuff too?

I guess I do need to get that book, everyone keeps saying it - thanks Dave.

[carastro]

I take it for 30 second exposures I don't need all this guiding stuff too?

You won't need to do guiding for 30 secs, but you will want to do longer exposures as you progress, so guiding is a must for the future.  If you get a telescope with a 50mm finderscope, you can often use this as your guidescope.

Carole 

[iksobarg]

Because good imaging friends don't let friends pink splodge.

[Starlight 1]

Hi tony The Heq5 is good for 18kg so keep imaging gear to  12kg max.

[RichM63]

Sadly the misinformation continues. Previously apparently the older 150/750 tubes were unfocusable with a DSLR, however my blacktube Explorer 150P is focusable with my Canon 700D. (no mod's required).

The EQ3-2 is somewhat flaky when fully kitted out but you can 'get away' with shorter exposures, use a remote camera control to trigger and don't stomp around the mount.

I don't know anything about the D80 it could be that is where the problem lies IDK. But before spending anythng I would practice with what you have. Aim for super accurate balancing, and great collimation + alignment. (always useful to know).

My EQ3-2 was fine for use with the webcam +150P although it has now been moved over to a dedicated wide field or Camera + lens setup and the 150P goes on the EQ5.

I'm only just starting out with image capture and the clouds are not playing ball, but there is so much that can be learned even with fairly basic kit and no extra outlay.

See if you really enjoy the work before spending more on it.

Just my 2p.

[t0ny]

Thanks Rich, that sounds like the most sensible thing to do for now. FLO are out of the HEQ5 Syntrack until at least February anyway so i'll either get really into it or fail to focus the thing and get nowhere.

I have a remote camera trigger so I'll try my best to give this a go with what I have.

'Aim for super accurate balancing, and great collimation + alignment' is the bit that scares me most yet I guess it's the most important?

I don't have one of them polar scopes and did not really want to spend any more on kit I intend on selling.

Is this what I need (and would you say it's essential for AP)? http://www.wexphotographic.com/buy-hm5-polar-alignment-scope-for-eq3-2-mount/p1526243

AlsoI have no idea how collimated (is that how you say it) the scope is. Probably terrible since it's been boxed and through a house move.
Do I need to buy a laser thing to do that? Perhaps this: http://www.wexphotographic.com/buy-sky-watcher-laser-collimator/p1526304

I think I'll be way more persistant if I know things are set-up correctly.

Thanks again for all the help!

[Starlight 1]

I am in Norwich if you are looking at any help.

Les

[t0ny]

Ah wow thanks Les that would be great!

[Starlight 1]

Give it  a day or 2  ,then do a dry run by day and check your collimation ect.

[Chris]

'Aim for super accurate balancing, and great collimation + alignment' 

A quick way to check collimation is to stick a moderately high power eyepiece in the focuser and get a bright star in the centre of the field of view. Then defocus the star, is it like a doughnut with the inner ring concentric to the outer ring? If so then the primary is collimated, if not then the scope will need to be collimated to get the best out off it.

Read this

http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide.htm

Once collimated, these 150p's stay put quite well unless knocked, so a quick check now and again is all that's needed

Allignment for the mount is known as polar allignment, see the link below:

http://www.astro-baby.com/simplepolar/simple_polar_alignment.htm

Now as for super accurate balancing. Not scrictly true. If your mount is tracking with the counter weights rising to the east, then you want the mount slightly east heavy by moving the weights slightly down the bar. This is because of backlash in the gears. If you have it super accurately balanced then the mount will be bouncing around the backlash in the mounts gearing, but if you load it slightly to the side that's rising then the gears will be held in contact together thus reducing the effects of backlash