Dew Shield

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pdmphoton
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Dew Shield

Post by pdmphoton »

Hello fellow Solar imaging fans.

I have a 140mm APO Doublet for wish I would like to purchase a front mounted D-ERF.

This particular 140mm scope is housed in an oversized 152mm tube, which translates into a very large diameter dew shield.

I am wondering with a front mounted D-ERF if the dew shield is really going to provide any advantage at all for daytime viewing in Arizona.

I will be using the scope with a Quark Chromosphere, which realize, technically does not require a front mounted D-ERF, but I feel it will deliver an advantage.

I am thinking a 135mm diameter D-ERF would fit the bill
and losing the dew shield will allow for a much smaller diameter cell holder.

I would appreciate any feedback

Thank you,
Paul Margolies


Lunt LS80Tha DS
APM 140 Doublet
Skywatcher 180mm Mak
Celestron C11 XLT -Hyperstar V3
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Re: Dew Shield

Post by marktownley »

Hi Paul,

A 135mm DERF would work well, this would generally be stopped down to 125mm in the cell which would give you a nice f ratio for the Quark.

Something like this might fit? Depends on the exact diameter of the dew shield

https://astrograph.net/epages/www_astro ... RF135C-167

or

https://astrograph.net/epages/www_astro ... RF135C-156

Mark


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Re: Dew Shield

Post by Montana »

I have exactly what Mark suggests and it fits very well on my TEC140. You can just about see it on my image here

https://www.flickr.com/photos/alexandra ... 535593245/

Alexandra


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Re: Dew Shield

Post by pdmphoton »

Thank you Mark and Alexandra,

1. The APM 140mm has a huge oversized tube and dew shield. I was thinking of removing the dew shield so this cell could fit the tube diameter.

Do you see any issue with that, as neither dew or stray light should be a problem imaging during daylight hours here in Arizona?

2. Do you know if Astrograph will ship to the US.?

Cheers,
Paul m.


Lunt LS80Tha DS
APM 140 Doublet
Skywatcher 180mm Mak
Celestron C11 XLT -Hyperstar V3
Quark Chromosphere
ZWO 174 and 183 Mono
iOptron CEM120
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Re: Dew Shield

Post by Dennis »

I dont use a dewshield on my 150/1200 Achromat, i dont see much gain there for solar observing / imaging and therefore had the filtercell designed accordingly. Without the dewshield the whole thing is much more easy to handle too. But others might have different opinions.


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Re: Dew Shield

Post by Rusted »

My 160mm D-ERF cell clamps directly onto the nose of the 150/10 iStar objective with Nylon thumb screws.
I cap the D-ERF cell when not in use.

P1440038 rsz 500 derf istar.JPG
P1440038 rsz 500 derf istar.JPG (34.88 KiB) Viewed 1372 times


http://fullerscopes.blogspot.dk/

H-alpha: Baader 160mm D-ERF, iStar 150/10 H-alpha objective, 2" Baader 35nm H-a, 2" Beloptik KG3,
Lunt 60MT etalon, Lunt B1200S2 BF, Assorted T-S GPCs or 2x "Shorty" Barlow, ZWO ASI174.
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Re: Dew Shield

Post by Dennis »

Rusted wrote: Thu May 12, 2022 9:22 am My 160mm D-ERF cell clamps directly onto the nose of the 150/10 iStar objective with Nylon thumb screws.
I cap the D-ERF cell when not in use.


P1440038 rsz 500 derf istar.JPG
looks cool that pipe and connection.. like a industrial flange : )


Triband C9.25
H-a: Quark Chromosphere with BF mod
WL: Antlia 500nm/ 3nm, 393 nm/ 3nm
Ca-K: homebrew (includes 2x 1.5A filters, thanks Apollo)
Player One Apollo Max + Mars MII
Barlows:
-2x Gerd Düring 2.7x
-2x TMB 1.8x
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Re: Dew Shield

Post by Rusted »

Dennis wrote: Thu May 12, 2022 11:20 am
Rusted wrote: Thu May 12, 2022 9:22 am My 160mm D-ERF cell clamps directly onto the nose of the 150/10 iStar objective with Nylon thumb screws.
I cap the D-ERF cell when not in use.


P1440038 rsz 500 derf istar.JPG
looks cool that pipe and connection.. like a industrial flange : )
The largest diameter [flange] is a Baltic Birch plywood counter-cell. :D


http://fullerscopes.blogspot.dk/

H-alpha: Baader 160mm D-ERF, iStar 150/10 H-alpha objective, 2" Baader 35nm H-a, 2" Beloptik KG3,
Lunt 60MT etalon, Lunt B1200S2 BF, Assorted T-S GPCs or 2x "Shorty" Barlow, ZWO ASI174.
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