travelling to bush with telescope

starry · #1 27-09-2010, 08:17 PM

wanting advice on a durable telescope to take on a 4wd trip to the kimberlies next year i have a bintel 250 mm dobson a bit to fragile i think for this type of usage maybe /about $1500 -$2000. to spend

mental4astro (Alexander) · #2 27-09-2010, 09:08 PM

Hi Starry,

Ambitious trip you aim to undertake. Firstly, I'm assuming you're no dill when it comes to the Kimberly!

You're right about the typical GSO/Bintel dob being too sensative. However, if you are prepared to take to it with a "hammer and saw", you should be able to fashion yourself a compact and durable compact dob.

The 10" dob I made has a pedigree of the such. It was fashioned on a design that saw its forefather do a similar trip as you are planning, right here in Oz:

http://www.atmsite.org/contrib/Ravneberg/alice/

I've seen this design taken upto a 17.5" puppy.

My 10" has been on trips with me too by 4WD. Of course, you will need to collimate regularly with all the bumps, but the design is rugged. Collimating is not a big deal, and is done quickly. And if you at least are able to make a decent dust-prove bag to seal your scope, you will be richly rewarded with the views. I've included a couple of pics of mine.

Dust will be the worst enemy you will have. However, if you can dust proof as best you can, a 4" to 8" Maksutov or Schmidt Cassegrain scope could be your best options if the above rebuild doesn't appeal. Have a look at the Andrews website for their Celestron range as their prices fall within your parameters.

Bon voyage!

Mental.

JethroB76 (Jeff) · #3 30-09-2010, 09:08 PM

Quote:

Originally Posted by mental4astro

However, if you can dust proof as best you can, a 4" to 8" Maksutov or Schmidt Cassegrain scope could be your best options if the above rebuild doesn't appeal. Have a look at the Andrews website for their Celestron range as their prices fall within your parameters.

Supposing a well sealed pelican-style case was used to store an 8" SCT for such a trip - how would it fair in regards to the need for collimation - would that style of scope be more or less susceptible to movement of the mirrors than a reflector?
Is collimation of a SCT similar/easier/harder than with a reflector?

starry · #4 30-09-2010, 09:30 PM

Quote:

Originally Posted by mental4astro

Hi Starry,

Ambitious trip you aim to undertake. Firstly, I'm assuming you're no dill when it comes to the Kimberly!

You're right about the typical GSO/Bintel dob being too sensative. However, if you are prepared to take to it with a "hammer and saw", you should be able to fashion yourself a compact and durable compact dob.

The 10" dob I made has a pedigree of the such. It was fashioned on a design that saw its forefather do a similar trip as you are planning, right here in Oz:

http://www.atmsite.org/contrib/Ravneberg/alice/

I've seen this design taken upto a 17.5" puppy.

My 10" has been on trips with me too by 4WD. Of course, you will need to collimate regularly with all the bumps, but the design is rugged. Collimating is not a big deal, and is done quickly. And if you at least are able to make a decent dust-prove bag to seal your scope, you will be richly rewarded with the views. I've included a couple of pics of mine.

Dust will be the worst enemy you will have. However, if you can dust proof as best you can, a 4" to 8" Maksutov or Schmidt Cassegrain scope could be your best options if the above rebuild doesn't appeal. Have a look at the Andrews website for their Celestron range as their prices fall within your parameters.

Bon voyage!

Mental.

mental4astro (Alexander) · #5 30-09-2010, 09:48 PM

Meade & Celestron SCT's have extremely well secured primary mirrors. The way they are designed, collimation can only be achieved via the secondary. Mak's cannot be post factory collimated as far as I know.

I've had my Celestron C5 for nearly 20 years. It too has done several thousand kms. It might need a tweek, but I still wouldn't bother its image quality is still so good.

Collimation seems to hold some sort of curse quality in its name. There is no mystery to it. It is just a tiny tweeking of the mirrors. The mirrors are deliberately held in cells that allow for these adjustments. If they were held static, there runs the risk of them actually breaking, or if knocked, then not being able to be realigned.

The tools that are available today make the process so much quicker and easier than ever. I don't see it as an obstacle to choosing a newt over some other optical system. For me, other factors are more important.

Collimating an SCT is much more sensitive a process. They require similar tools as reflectors, but specialized to them.

Refractors are the other optical type that doesn't need collimating.

AstroJunk (Jonathan) · #6 01-10-2010, 12:19 AM

Quote:

Originally Posted by starry

wanting advice on a durable telescope to take on a 4wd trip to the kimberlies next year i have a bintel 250 mm dobson a bit to fragile i think for this type of usage maybe /about $1500 -$2000. to spend

without a moments hesitation: buy this http://www.iceinspace.com.au/forum/s...ad.php?t=60829

It is the perfect size for travel and is tough as!

(I can't believe its still for sale - people around here don't appreciate grade A optics!!!!)