Celestron 9.25 SCT

[Aster]

I have been investigating the C 9.25 on a CG-5 GoTO or putting the C 9.25 on my standard EQ6 Mount (no goto).

Some while back before I became a member of IiS there were some dicussions on this subject. Plus some members have used or are still using a C 9.25 on CG-5.

Can someone give me an overall view how good that setup with a guidescope would perform for DSI ?

Also, importing from Canada or USA, would I have to pay import duty or GST even if it is send as a Gift ?

According to OPTCORP they can't sell to me direct but can go through someone in the states for me.

Again, a little while ago there was a thread along them lines but I can't seem to locate exactly what I am after. Would appreciate some advice/help on that matter.

[citivolus (Ric)]

Importing via an agent in the USA would have cost me about $1200 US for this OTA plus a CGE mount, on top of the 10% GST on import and the customs administration fee.

In my case, CGE + C9.25 for you to use as an example:

4029 USD new
+ ~1200 USD agent/shipping fee, including UPS expedited and export documentation
+ 10% ($530 USD)
+ estimated $50 customs administration fee (that is what they wanted to process my Megrez 90 import, it may be higher depending on the value of the item)

for a total of at least $6600 at current exchange rates. Purchasing domestically would be $8000.

Direct import, assuming you could find a used scope or vendor willing to ship, would be about $6000. That is a 25% savings, more than enough to cover returning the entire OTA and mount to the USA for service should you experience catastrophic failure; you just won't be getting an over the counter exchange. Put another way, that savings is more than the cost of the OTA in the USA, and 2/3 the cost of the mount.

My personal advice is that if you want more or less hassle free and have the funds, purchase domestically, otherwise importing may be the way to go. You have to decide where it sits on your own comfort metre.

[g__day (Matthew)]

Its possible - but its right at the limit of what a CG5 can do - plus the Celestron dovetail that mates to the CG5 is a weak link when you're going for stability of your rig.

My advice would be get a light ed80 and mount it on top of the C9.25. I love the Carbon fibre C9.25 as it keeps focus beautifully even with significant temperature changes,

I put my CG-5 on a pier, used a CGE bar to on the top to attach O rings to hold a (too heavy) Megrez 80mm. Ran an 3" extender to achieve focus into a Meade DSI -> PHD -> ShoeString Astronomy parallel port -> 6 pin cable -> CG-5 auto-guide port. It worked and kept costs low. I imaged from a Canon 400D on Manual Bulb mode driven via a ShoeString adapter into a PC via DSLR Shutter software from stark-labs.

This set-up will work, but it needs care and it right at the limits of the gear's performance.

I added a Meade motorfocuser, then switch to a second hand Vixen Atlux (pure magic), then added Losmandy dovetail bars (greatly improved rigidity) and now am playing with software to better tune my rig!

[Aster]

Citivolus,

Thanks, interesting figures, whats the +10% for ? May have found a way going via acquaintance/friend in the US. Still working on it if I should go ahead.

G_Day

Thanks for the advice. What is the C9.25 like optically? Liked the idea of the GOto with autoguiding port and objects easy to locate for imaging. But may only go for the TAO and update my EQ6, which may leave me some funds for a Canon DSLR.

Have my EQ6 head (no GOTO) also pier mounted with a 250mm F6 Newt on top. 100% improvement in stability. But seeing I have to constantly carry the 15kg tube around 20m, including up steps, out of the garage when I want to do some observing or imaging I was looking for something smaller in seize and weight in my prize range so I can continue enjoying my hobby. Getting just to old to carry heavy
weights around.

Have an old 80mm Unitron Spotting scope, good quality achromate, which I am at the moment converting to a guide scope.

[g__day (Matthew)]

Personally I really like the C9.25 optically. I haven't had too many other scopes to compare it to (a 6" Newt, a 5" MAK and a 80mm refractor), but it has a beautifully flat field and finds focus well. My next scope will probably be a 4" - 5" apo once I've saved up a bit (alot)!


So given my seeing conditions and limited experience with viewing and not having the chance to view through a broad range of different scopes
I am quite happy with the C9.25. It performs to spec and is a delight to use.

The only scope that every left me with a OMG chill was Zane's 24" Obsession at Magellean - under very dark skies it really was a magical experience!

I've loked through 16" SCT at Macquarie Uni's labs - and 10" SCTs - but too long ago to really recall with detail how well they performed.

I think the EQ6 is a practical starting platform for imaging so long as you keep it within its capabilities. As I am finding on a mount that costs circa 3 times the eq6 with similar carrying capacity - longer > 10 minutes
imaging at long focal length (2.3 metres) is quite tricky - my auto-guiding is not giving me what I need yet. I just checked to day on a shot with streaks I'm 20 arc seconds of RA drift adjustments out in my guiding of a 20 minute duration shot. So 1 arc second per minute RA drift is enough to ruin things.


In the shot below - the 150 mm length is 30 arc minutes so 1 mm = 20 arc seconds. By my ruler bright stars are 1 mm in diameter ~ 20 arc seconds, and drift is 1 mm - making stars into clyinders 2mm long - 20 20 arc seconds drift in a 20 minute shot. So close to perfect but so far away!

Why I am out is what I am working on now - it might be optical limits of my gear, seeing conditions, poor tuning of my set up etc. Until I can track the source of my problem I can fix it and see where the limit of my gear is. The point is your choice of targets and calibre and tuning of your gear limits what you will be able to achieve. Keep within those limits and you'll be happy.

Imaging is like this - your choice of target defines what you can aspire to on a certain level of gear. At present I'm hooked on faint planetary nebulae - so I've picked up the hard basket!

[Aster]

g_day

Thanks for that info.

I can go upto 4-5 minutes unguided. Spend some hours drift aligning, taking appart the EQ6, cleaning, adjusting bearings, worms and gears.

The only thing now is atmospheric seeing/turbulance and fluctuating power. Am seriously considering something to give me a constant mains power input. Must talk to my electronic expert

If you have your mount permanently mounted on a pier and reasonable drift aligned to the SCP I can not understand why you have so much drift with autoguiding. The Tarantula is not that far of the SP, circumpolar, which should give you very little drift even with a badly aligned mount.

Are you sure you don't have a balance problem somewhere ?

[g__day (Matthew)]

Not sure where the problem arises from - could well be balance!

[citivolus (Ric)]

The +10% is GST which will be charged by Australian Customs on the import prior to releasing it to you, if the combined value of items in the shipment is over $1000 AU.