SW 130-pds secondary mirror dew

[tingting44]

hey guys, just wondering how other 130-pds user's deal with secondary mirror dew?

i was thinking of a DIY yoga mat made into a dew shield

then  was thinking of one of these secondary heaters from kendricks...

http://www.kendrickastro.com/newtonian.html

then saw these from FLO

http://www.firstlightoptics.com/dew-prevention/astrozap-flexi-heat-dew-shields.html

just wondering what others to, that is most effective, as i need something as secondary dew stopped me dead in my tracks saturday night after only 4 x10min subs.....not good

[sidelight]

I use a cut up flower pot dew shield and wrap a dew heater around the base of that (http://stargazerslounge.com/topic/209782-cutting-the-cost/).  I did use a mat but live on a hill near the coast and the odd gusts were changing the shape of the dew shield so flats were often a nonsense.  I have found that enough to stop dew on my secondary.

Cheers

Ross

[Leveye]

I'm on the coast so lots of dew issues.The Kendrick works great. I bought it used and then a 3 dollar dial control for it. Real pleased with the results. I run it and one for my main scope off of my mount and computer gell cell battery and it does not use that much extra juice.

[PorkyB]

I use a camping mat dew shield and it works most of the time.  To make the dew shield I wrapped bands of strong tape around it as nothing much sticks to the mat material itself.

I have still had secondary dew a couple of times and it is incredibly frustrating to lose imaging time this way, especially when you think everything is going OK.  I have to confess that I wiped it off with my glove and took the images again.

The Kendrick heaters look good but they are expensive.  Maybe I need a trip to Maplins for some resitors, plug, wire and a soldering iron.  There should probably be a fuse in there somewhere as well.

[tingting44]

thanks for all your tips guys, i have to admit im not to thrilled about removing the secondary mirror for the dew heater lol, ive never touched the secondary before..... think i might go with the camping mat or yoga mat

edit, has any one actually used one of these on there 130-pds as FLO said it might cause diffraction problems, but was not sure and to ask here?

http://www.firstlightoptics.com/dew-prevention/astrozap-flexi-heat-dew-shields.html

[Uranium235]

Mines about 12 or 14" long (oo-er)...lol. Its made from foam underlay used for laminate flooring, and I blacked the inside with black card. Its also rigid enough to support a b-mask (no need to remove dew shield when focusing).

Never needed a heater before - except on the dampest, bleakest winter nights. If youre stuck with dew and need an emergency fix, I usually deploy the hairdryer for a couple of min - then point choose something lower in the sky to image - that way the dew wont make a comeback.

[tingting44]

Mines about 12 or 14" long (oo-er)...lol. Its made from foam underlay used for laminate flooring, and I blacked the inside with black card. Its also rigid enough to support a b-mask (no need to remove dew shield when focusing).

Never needed a heater before - except on the dampest, bleakest winter nights. If youre stuck with dew and need an emergency fix, I usually deploy the hairdryer for a couple of min - then point choose something lower in the sky to image - that way the dew wont make a comeback.

Thanks for your input Rob

think im going to go with a camping mat from GO outdoors for £10, then stitch some Velcro to the camping mat, and stick some Velcro on the 130-pds and that should be good to battle the dew then hopefully, its the 1st time ive ever had dew problems with the 130-pds and I didn't like watching my stars disappear more and more from sub to sub, I was getting the best data ive ever had, 1st time at my dark site in god know's how long, only to get stopped in my tracks on the Iris nebula after x4 600sec subs

[tingting44]

well i just got back from GO outdoors, got myself a camping mat to make my dew shield, ive cut enough off the mat to go around my scope, id love to see some pics of people's homemade dew shields with camping mats or the like as im finding it quite awkward  to get the mat the same diameter all the way along.... im thinking to either attach it with sticky back velcro or cable ties....again id love to see some of your pics if its not too much trouble

[sidelight]

When I used a foam dew shield I found if I taped it so it was very slightly stretched to fit it would hold itself on quite happily, I used velcro as then I could take it apart and store it flat.  The shape changing and that it fell apart after a year was one reason I ended up with the stiff flower pot, with some flocking inside and http://www.amazon.co.uk/Astro-dew-heater-50-telescope/dp/B00FCGP6XS/ref=sr_1_3?s=electronics&ie=UTF8&qid=1407230162&sr=1-3&keywords=W%26W+Astro+dew+heater wrapped about the base where it is attached to the scope.  

Cheers

Ross

[tingting44]

When I used a foam dew shield I found if I taped it so it was very slightly stretched to fit it would hold itself on quite happily, I used velcro as then I could take it apart and store it flat.  The shape changing and that it fell apart after a year was one reason I ended up with the stiff flower pot, with some flocking inside and http://www.amazon.co.uk/Astro-dew-heater-50-telescope/dp/B00FCGP6XS/ref=sr_1_3?s=electronics&ie=UTF8&qid=1407230162&sr=1-3&keywords=W%26W+Astro+dew+heater wrapped about the base where it is attached to the scope.  

Cheers

Ross

Thanks for the tip russ, does it matter if its not the same diameter all the way along? its quite horrible stuff to work with, i got the more expensive one @ £13 which is more stiffer than the £8 as i thought it might be more strong, it is lol, maybe i should have gone for the cheaper thinner one.... 

how did you attach your velcro to the mat? as im not sure ill get a good surface to stick something on the mat because of the material the mats made out of,

my 1st two ideas were cable ties, but this way it would not be so easy to remove for transporting to the dark site.... or velcro, but again not sure the velcro will stick securely on the mat..... i suppose i got a couple weeks to play about with different ways as the moon is back out again for the next fortnight...

[sidelight]

I would ensure it is slightly wider at the front, In the end I took my scope out of its tube rings and using the end opposite the focuser to get the right size.  I used velcro with adhesive tape on the back that seemed to do the trick for me (I did have to patch it with some double sided carpet tape a few times).  

Cheers

Ross

[tingting44]

I would ensure it is slightly wider at the front, In the end I took my scope out of its tube rings and using the end opposite the focuser to get the right size.  I used velcro with adhesive tape on the back that seemed to do the trick for me (I did have to patch it with some double sided carpet tape a few times).  

Cheers

Ross

Thanks Ross for them tips

one more thing did you overlap it to join it

[sidelight]

I did, overlap and velcro up so it could be stored flat.