Opinions on the Nexstar 5SE as a beginner scope

Post by **weixing** » Sun Feb 24, 2008 8:50 pm

Hi,
Singapore is very humid. If you check the weather forecast, the relative humidity is usually from 70% to 95%.

IMHO, dew shield is basically a must in Singapore for SCT user, unless your observation site is usually windy (dew usually won't form if it's windy) or you don't plan to observe past mid-night. The dew shield will not only delay the dew formation, but also act as a light shield to block stray light... For SCT, it also make the front of the SCT a bit heavier and allow the scope to balance a bit easier.

By the way, a 2x barlow will also be a nice addition as you'll be able to get 3 magnification (2 magnification if your diagonal is screw on type) out of a single eyepiece. For example, a 25mm will basically give you 50x, 100x (with 2x barlow insert on the diagonal) and 150x (with 2x barlow insert before the diagonal).

Happy observing and have a nice day.

codenamejag · Post by **codenamejag** » Sun Feb 24, 2008 10:19 pm

thank u Meng Lee, tungkian & weixing for your info.... right now i'm quite confused. is there a difference between a dew heater and a dew shield and dew removers (heater strips)? which should i get to use with the 5" SCT?

Post by **weixing** » Sun Feb 24, 2008 10:34 pm

Hi,
Take a look at this SCT website for SCT, it's quite useful:
http://sctscopes.net/index.html

is there a difference between a dew heater and a dew shield and dew removers (heater strips)? which should i get to use with the 5" SCT?

Check out the dew prevention section on the above website:
http://sctscopes.net/SCT_Tips/Need_to_H ... ntion.html

Have a nice day.

Sam Lee · Post by **Sam Lee** » Sun Feb 24, 2008 11:55 pm

Hi,

You can easily make your own dew shield out of simple cardboards or equivalent (water resistant material is even better). Just coil it around the front part of the scope like a pipe. This will effectively minimise the chance of dew landing on your scope when you observe through the night.

However, if you are observing in Singapore, most of the time it will be used to keep out stray lights instead.

Forget about the dew heaters or removers. You will only need those when you get out of the urban SG areas. I have never had any dew problems when observing in Singapore. Even so , getting heat packs are much more cost effective than dew heaters.

Post by **weixing** » Mon Feb 25, 2008 12:24 am

Hi,

I have never had any dew problems when observing in Singapore.

Hmm... strange?? Where do you observe?? Dew is quite serious in Tampines. Dew usually start to form on all my stuff after a few hours of observation especially after mid-night, unless it is windly. Most of the time, my bag, star chart and outside of the tube is wet after my observe session. That's one of the reason why I prefer Newtonian which basically don't have dew problem as the tube itself act as a large dew shield.... hmm... if I remember correctly, only one time the dew is so serious that my secondary mirror and eyepiece dew up...

Have a nice day.

Sam Lee · Post by **Sam Lee** » Mon Feb 25, 2008 1:29 am

Haha, thats weird. I've observe in Woodlands , Jurong , last time in SP , its unusual for me to get dew problems.

Perhaps the area where you observe in is nearer to large forested areas etc ?

MooEy · Post by **MooEy** » Mon Feb 25, 2008 2:29 am

dew do form out there in the field. just that how much forms on ur scope may vary alot. most nights i have no problem with just the dew shield on my refractors, but for those long sessions in mersing, even with the extra extra long dewshield on the 3" toy scope, it does dew up.

a dewshield is very useful, esp in sg since it helps to block out stray light as well. for an sct it's even more useful due to the corrector plate infront. it keeps out dew and unwanted fingerprints.

~MooEy~

codenamejag · Post by **codenamejag** » Mon Feb 25, 2008 11:13 am

think i'll hav to try things out n see if i need to get the dew shield....

Meng Lee · Post by **Meng Lee** » Mon Feb 25, 2008 12:40 pm

In the case that dew forms on the corrector plate, please do not wipe it off to prevent scratching the optics. Point the tube downwards and let it evaporate slowly.

Post by **weixing** » Mon Feb 25, 2008 12:51 pm

Hi,
By the way, if you keep the scope in the dry cabinet, don't put the cover on. If you do so, fungus might still grow if too long didn't use as the cover will trap the moisture inside.

If you don't have a dry cabinet to keep the scope (like me), you can do the following:
1) Use it often,
2) Air it often,
3) Expose to sunlight regularly.

Have a nice day.