Hello from another newbie

[jashwood]

Hi there :)

I'm a newbie from Brisbane and thought I'd say hello, and ask a few questions.

I'm using a secondhand 10" collapsible dob which I bought from an ad here - it came with about a dozen eyepieces, filters, and 1.25 and 2 inch barlows.. so far it has been great. The seller was awesome and showed me around the scope at night when we met - which was fantastic. I've also learned a lot by reading posts on this forum..

So I've been observing for a while and have got a few questions....

This dew thing... how long roughly will a dew shield keep dew off the secondary on a really wet night? I'm wondering if a heat source is worth looking at or whether a dew shield is enough - having to travel out of town to dark skies it would be great to know it can be kept out one way or the other.

Was also wondering, how good are the high end eyepieces like the televiews... They're expensive - but are they worth it?

Cheers :)

Josh

[Brian W]

You open a can of worms with your question about eye pieces. The question is not 'are they worth it' the question is 'are they worth it to you'?

About the only way to find out is to go to a star party or over to someone you know who has the ep's you are wondering about and try them out.

I realize that does not answer your question and that there will be others with experience as good as mine or better who can and undoubtedly will give different answers but in my opinion 'trying before buying' is always good, if not always practical, advice.
Brian

[Blue Skies]

They are worth it, but don't go all out at once. One at time, trying it out thoroughly before filling in another gap in your collection is a good way to go.

Eyepieces are quite individual choices - what one person like the next may hate, or one might work better in one scope than another type of scope - so there is no definitive brand or model to recommend. Ideally borrowing and testing in your own scope is a good way to go, or join in an observing group and seeing how their eps perform in their own scope is a good way to go before purchasing, but it isn't always possible. I think any of us who have been observing for some time have some old eps tucked away that are considered 'no good' anymore.

[Suzy]

Hi Josh :welcome:

Have a read of one of my recent threads- it has some great information for dew control and even tells you how to make a dew shield in one of the links.
http://www.iceinspace.com.au/forum/showthread.php?t=75097&highlight=dew+suzy

Regarding eyepieces, Brian and Jacquie have given you great advice.

You're not wrong there. :rolleyes:
Some of us even get into fisty cuffs over it :rolleyes:. Even me, a lil' gentle girly girl has turned into a monster over it. :rolleyes: A good eyepiece thread will bring about some sparring and two of the threads listed in the links I've given do just that. :rolleyes:

And my 2c worth...
Use what you have for the time being and don't rush into it- what you're after will become fairly apparent soon enough once you've been using the scope for a while.
Eyepieces are quite an involved. ;) Have a good look through the Eyepieces forum, you'll learn lots there.

Also, I have done a couple of really informative threads on eyepieces if you want an idea what to look for in premium quality...

Choosing a premium 14mm (by me)..
http://www.iceinspace.com.au/forum/showthread.php?t=71653


Choosing a premium 5mm (by me).. (which, by the way, turned into a 10mm in the thread)
http://www.iceinspace.com.au/forum/showthread.php?t=59484& (http://www.iceinspace.com.au/forum/showthread.php?t=59484&highlight=5mm+suzy)
highlight=5mm+suzy (http://www.iceinspace.com.au/forum/showthread.php?t=59484&highlight=5mm+suzy)


Thread titled "We have $400 to spend"
http://www.iceinspace.com.au/forum/showthread.php?p=718343#post718343


Some general reading on understanding eyepieces...
http://www.cloudynights.com/item.php?item_id=1338

http://www.eaas.co.uk/cms/index.php?option=com_content&view=article&id=4:a-short-guide-to-choosing-eyepieces-by-neil-paterson&catid=5:learning-zone&Itemid=8


And lastly, I'm throwing in this link for an article, because it explains the introduction into astronomy very nicely. Written by Sky & Telescope magazine, one of the comments written rings so dear and true.. http://www.wwnorton.com/college/astronomy/astro21/sandt/startright.html

[jashwood]

Thanks very much for the advice, appreciate it!
A good planetary eyepiece would be great - looking at planets and the moon has become a habit..

I've got TMB Super planetary 6mm and 9mm and got up early the other morning to look at Jupiter for the first time... to me it seems those eye pieces aren't too bad... it was an amazing sight, I really wasn't expecting to see the cloud bands so clearly :)

Which got me thinking... wow, I wonder how Jupiter and Saturn look through those really expensive Televue eyepieces I see people talking about on astronomy forums! So thanks for the links Suzy will check them out :)

I've only been to a reasonably dark sky with the scope once, sadly it clouded over within an hour of starting - but I was amazed how much more detail came out .. the jewel box suddenly seemed surrounded by thousands of stars in the wider field eye piece.. I mean I was expecting a dark sky to make a big difference, but not THAT much difference! It was like another sky up there.

Thanks again for the tips!

[michaellxv]

Hi Josh,

This (http://www.iceinspace.com.au/forum/showthread.php?t=77671) is my recent experience with adding shroud around my Lightbridge. Makes a world of difference so try something similar before you go spending on heating.

[big_dav_2001]

Hi Josh, welcome to IIS!

I opened a thread a while ago about dew control for my solid-tube GSO dob and was told to avoid heaters because as soon as heat comes into play, thermal air currents form in the OTA and a warm "boundary layer" of warmer-than-ambient air forms around the primary and both can degrade the quality of what you're seeing. Its important to keep your scope as close to the ambient air temperature as possible, but to keep the air moving in order to prevent dew build-up. I was directed to this article and found it very helpful;

http://www.iceinspace.com.au/63-400-0-0-1-0.html

I've since made a plate out of thin plywood for the rear of the OTA with a cut-out for the collimation screws and the fan and attached it with Velcro, doing this along with the internal baffle described there has virtually eliminated all dew problems I was having.

I'm not sure if it will work with the secondary on your scope though because the open truss/collapsible tube may prevent the air current from reaching the secondary, but I think it should at least keep the primary from dewing up whilst preventing any warm air currents caused by heaters from affecting your seeing (again, not that you should have any air-current problems with your truss design).

Possibly the article fix along with a dew shield and shroud may be enough to get the air moving inside your scope and keep the dew off your mirrors whilst staying at the ambient temperature and limiting thermals.
Davin
:cheers:

[big_dav_2001]

Sorry Michael, I should have read your link first, that's exactly what I was describing in my last post, and should work well.

Davin
:cheers:

[michaellxv]

There's more than one way to skin a cat and we don't know exactly which scope Josh has. :cheers:

[big_dav_2001]

Good point :) it definitely worked wonders for me, had big dew problems to begin with, did the mod a couple of weeks ago, and managed to stay out all night last week without a single speck of dew afterwards (got down to -3, frost everywhere but not a single bit on either mirror, I was pretty impressed :thumbsup:). And the fix only cost me bout $25 worth of plywood, Velcro and draft-stopper tape. Nothing better than a cheap yet effective fix to an annoying problem :)