Adding a scope to SA + dslr

[cadman342001]

My plan is to get a scope for my Star Adventurer set up with my dslr and at some point after my month in the GC I'll upgrade my mount to say the HEQ5 Pro. I only have old heavy lenses with a max FL of 200mm and don't plan on getting any.

Would this be a good starting point ?

http://www.astropetes.com.au/telescopes/Skywatcher_ED80.html


Not much more $$$ but 1.5xFL = this

http://www.astropetes.com.au/telescopes/Skywatcher_ED100.html


Looking to do mainly astrophotography obviously

What are your thoughts ?

Cheers

Andy

[pluto]

Both of those will be too heavy, and have too long focal lengths, for the SA. I was using a WO Star 71, which is much smaller and lighter, and it was about the maximum weight and FL in my opinion.

My advice - have fun with your lenses on the SA and get an ED80 when you get your HEQ5 :)

[cadman342001]

OK thanks Hugh

[Nebulous]

What problem did you have with the weight and focal length Hugh?

According to the SkyWatcher Australia website the Star Adventurer is good for up to a 5kg payload (the same as the Star Discovery mounts). I have a Star Discovery mount and it seems OK with a bit of weight. Indeed, one of the standard SD scope options is a fairly hefty 150/750 Newtonian. And, like Andy, I have wondered if one of the telescopes he is considering might be an option for me further down the track.

http://skywatcheraustralia.com.au/product/star-adventurer-wi-fi-kit/

They also say "The Star Adventurer Mount is an ultra portable equatorial mount kit ideal for small telescopes or for astrophotography with camera lenses up to 200-300mm in focal length."

So "in theory" Andy's camera and lenses, or either telescope, should be fine. Unless I've misunderstood something (always possible... ;) ). Even my hefty old Canon 7D with a thumping great 120-400mm zoom on it weights less than 3kg.

The two telescopes Andy linked to are quoted at tube weights of 3kg or less. So by the time he removes the lens from his camera and fits the body in place of the eyepiece he would still be looking at under 4kg.

But this is in theory... :) :) Where do you feel the catch is?

[pluto]

Hi Chris,
The catch is that longer focal length means tracking needs to be more accurate and longer focal length and more weight means guiding becomes more difficult. Good guiding is very dependant on good balance, and balancing a large/long and heavy scope on a SA would be difficult.

With my A7s on a WO71 (350mm FL) the pixel scale is about 5 seconds​ of arc per pixel - so if the error of the mounts tracking/guiding is more than that then you won't get round stars. In my experience that was about the amount of error I had when guiding and so my exposures were a bit hit and miss - and that's if everything else was perfect.
If I had my camera on an ED80 then the pixel scale would be smaller and I think most, if not all, of my subs would not have been usable. Of course most DSLRs have much smaller pixels (photosites) than the A7s so this would make the problem worse.

The rule of thumb is that, for astrophotography, you halve whatever the manufacturer rates their mount at.

I started out with a 5DmkII on an ED80 on an EQ5 (not HEQ5, bigger than a SA) and getting round stars was a challenge. Even getting nice round stars with a DSLR on an ED80 on an HEQ5 is not trivial let alone on a tiny mount like a SA.

Hope this makes sense! (Typing this on a phone is tricky!)

P.S. the Star Discovery mount, being an AZ-ALT mount and not an equatorial mount, is not really designed for astrophotography - so for visual use it's probably fine to push the mount to its limit weight-wise.

[cadman342001]

Thanks for seeking clarification Chris, I had assumed what Hugh has now elaborated on, that the 5kg limit is just theoretical and that in practical real world the scopes are too much for the SA but I should have asked.

eg my ball head is rated at 66 lbs !

[Nebulous]

Hi Andy,

Apologies for jumping in on your thread but I had been wondering something very similar.

Astrophotography seems to be exceptionally rich in traps and difficulties, so it always good to read the practical experiences of others. On paper the choices looked good, but....

All the best with your efforts - I'll be following your progress with interest, and probably wondering if my wallet (and my wife...) can stand the pressure of my attempting to follow in your footsteps! :D

[Nebulous]

Hi Hugh,

Thanks very much for such a thoughtful and informative reply. Very handy to read some first hand experience to put the manufacturer's blurb into perspective. :):thumbsup:

My main interest is in exploring the skies and 'learning the layout as it were. It seems that taking photos for that purpose is quite straightforward - just a regular tripod and some appropriate settings can capture a 'map' of an area of interest for later study. But going from "adequate" for that purpose to "good" when it comes to detailed closer work seems to require a quantum leap in time, knowledge, patience, and of course budget..! :scared:

My intention is to try and stick to exploration for a year or two and not be seduced by the lure of proper astrophotography. But I have a nasty feeling that the nature of the challenge, not to mention the attraction of acquiring more interesting equipment may eventually win out....

Cheers,

Chris

[DarkKnight]

As Hugh said "The rule of thumb is that, for astrophotography, you halve whatever the manufacturer rates their mount at."

This also applies to general photography with tripods and ball-heads. Mount 3 Kgs on that you beaut ball-head that is supposed to hold 30Kgs and watch your carefully composed shot slowly disappear from view. While it may well hold 30Kgs in a perfect vertical orientation, as soon as you move away from the vertical, gravitational forces kick in inducing the dreaded 'droop'.

For me, the operative word when selecting any mounting hardware is 'overkill' and this also gives you some future proofing 'coz you know, deep down inside, that you will soon want a bigger lens/scope. ;)

[pluto]

I know that feeling! You'll soon fall down the rabbit hole ;)

[raymo]

Perfectionists, and people with huge bank balances, believe that half
the manufacturer's stated max load is the max load for imaging, but
I have found in my 61 years of astro imaging that 75% is just fine in
most instances, and I used to sometimes use my Super Polaris at
around 90% without problems.
raymo

[pluto]

I'm neither, especially the latter! (Particularly after getting into this hobby...)
In my experience putting anywhere near 10kgs on an eq6 (rated at 20kgs), especially with a long ota, made it difficult to reliably get good long subs (>5mins). Of course my experience is only with Skywatcher mounts and I'm sure you could load up the likes of a PME, AP, Tak, etc mount to its limit and it will track, and guide, along happily all night.

You're right about perfectionists though and I guess it depends on your own threshold for the quality you want to produce, and the time and effort you want to spend fiddling with your setup.

[doppler]

I think these are the key words here, "made it difficult to reliably get good long subs (>5mins)." Difficult to set up but not impossible, it's just a lot easier with a lightweight system. Off course the whole purpose of using a fat fast newt is not having to use long subs. I have just finished setting up a 10" f5 newt on a HEQ5 pro mount (on an in ground pier) and it is guiding well with a 50mm finder guider. This set up is about 15 kgs, apparently a couple of kgs over according to some specs. There are a few others here that are also successfully imaging with maxed out mounts.

[cadman342001]

I've bought the HEQ5 Pro with Bressier Messier AR-127L + Plossl kit on the buy & sell section for $1200.

What are your thoughts ?

I was only going to get the mount but it made sense to pick up the whole lot cash wise.

Is the scope ok for astrophotog ? I can sell it on if not or just use it for viewing and pick up an 80, using the mount for astrophotog with my dslr and lenses in the meantime.

What about the Plossl kit, is that included with the scope as a retail package ? I'm thinking better than what you usually get with a cheap scope but not as good as quality eyepieces ?

Only relevant for viewing presumably as the dslr will be inline.

Andy

[cadman342001]

and of course I have the polemaster to carry over to the HEQ

[Shano592]

It is quite full down here, isn't it? :D

[doppler]

If it was me I'd keep it ya can't have too many scopes.
Probably not the best for photography being an achro and slow at f 9+ but might be good for the moon and planets. Visually should be great though.
An ED 80 is a great starter for astro photos with that mount.
That eyepiece kit is good enough to start of with, the visual guys put a lot of importance in quality eyepieces but astro photographers don't seem to care much about them.

[cadman342001]

Thanks Rick, I suspected as much but like I say I'll keep it for viewing, be nice for the Winged Serpent / the kids to have a look through. It was only an extra 350 for the scope and eye piece kit so I thought I might as well.
The mount has been used twice.

Andy

[DarkKnight]

Have fun with your new toys Andy. :)

[Larryp]

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