Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Blocking Filter Question: Solarmax 60

  • Please log in to reply
14 replies to this topic

#1 TerryWood

TerryWood

    Soyuz

  • *****
  • topic starter
  • Posts: 3,545
  • Joined: 15 Mar 2012
  • Loc: USA

Posted 18 November 2017 - 09:59 PM

This might be a dumb question, but are blocking/ITF filters the same in the Solarmax 1 and Solarmax 2 scopes? If I bought a new BF10 would it be safe in the older Solarmax 60? The blocking filter that I have looks good, but when I unscrew it (eyepiece side) and shine a light into the diagonal housing, I see some clouding on the backside of the ITF filter. However, the ITF filter still has a nice reflective coating when viewing it from the outside (telescope side of the diagonal). Is it safe to use in that condition? I know it's possible to change out the ITF, but I'm considering buying a brand new BF10 filter/ITF/diagonal, and then getting an upgraded ITF for the old BF10 unit a little later. In the interim, I've placed a Baader UV/IR Cut/L-Filter in the nosepiece of the diagonal in front of the ITF filter.

 

Thanks for any advice, I really appreciate it!

 

 

V/R

 

Terry


Edited by TerryWood, 18 November 2017 - 10:14 PM.


#2 Greg77

Greg77

    Ranger 4

  • -----
  • Posts: 307
  • Joined: 02 May 2009
  • Loc: Slovenia, EU

Posted 19 November 2017 - 04:44 AM

Why buying a brand new BF10 filter/ITF/diagonal if you can just replace ITF with Maier or Beloptic ITF? There is no problem with Coronado BF filter´s that I know about...

 

Just my two cent´s...

 

Here is the Photo of my old and new PST ITF....

 

ITF-old.jpg
ITF-new.jpg

 

 

Even if your ITF is in bad shape, still is safe to use, you get a little darker image at the eyepiece...

 

Greg


Edited by Greg77, 19 November 2017 - 04:53 AM.

  • TerryWood likes this

#3 TerryWood

TerryWood

    Soyuz

  • *****
  • topic starter
  • Posts: 3,545
  • Joined: 15 Mar 2012
  • Loc: USA

Posted 19 November 2017 - 10:11 AM

If I did decide to buy an ITF from Maier Photonics, is it a drop-in filter? It looks like it has RG630 in it as well, so hopefully that means I wouldn't need an additiinal filter in the train (besides the BF10, etalon, and ERF). I know I seem overly cautious, but I only have one set of eyes so I don't want to screw this up. I know Bel Optik is a very good one too, but requires additional filtration because it does not have RG630. It's a lot more expensive too. But I think it's the top of the line. Thanks again Greg! V/R Terry

#4 Greg77

Greg77

    Ranger 4

  • -----
  • Posts: 307
  • Joined: 02 May 2009
  • Loc: Slovenia, EU

Posted 19 November 2017 - 10:35 AM

BelOptik ITF is made of RG630 and KG3 glass...see on their homepage. It is a great replacement filter and direct drop-in, but you need to be carefull...filter orientation - direction of the lightpath.

Greg
  • TerryWood likes this

#5 TerryWood

TerryWood

    Soyuz

  • *****
  • topic starter
  • Posts: 3,545
  • Joined: 15 Mar 2012
  • Loc: USA

Posted 19 November 2017 - 10:58 AM

I'll probably go with the Maier ITF if it's also easy to install. I may give them a call tomorrow to discuss. Maybe I can send the diagonal assembly to them (since they are fairly close) and they can install the new ITF. In the interim, I'm leaning toward buying a new BF10 diagonal just to have a fresh filter assembly (and as a backup to the repaired diagonal). I'll have to give it some thought. V/R Terry

#6 BYoesle

BYoesle

    Fly Me to the Moon

  • *****
  • Posts: 6,829
  • Joined: 12 Jun 2004
  • Loc: Washington USA

Posted 20 November 2017 - 11:04 AM

 

If I did decide to buy an ITF from Maier Photonics, is it a drop-in filter? It looks like it has RG630 in it as well, so hopefully that means I wouldn't need an additiinal filter in the train (besides the BF10, etalon, and ERF).

 

Terry,

 

The Maier ITF only has AR coatings on the substrates. Therefore if you get the Maier ITF you will need an additional IR blocking filter to protect the ITF from thermal loading and cycling - the reason the ITFs fail. Coronado ERFs also have no such IR blocking. This is why you should either replace the ERF with a Baader, BelOptic, or Lunt ERF, which do have IR blocking, or use a secondary UV/IR blocking filter ahead of the ITF,

 

As Greg states, the BelOptik ITF replacement has a RG630 filter facing the objective with IR blocking applied for up to 1200 nm, followed by a KG3 filter for blocking out past 4000 nm.

 

However, if you use an ERF made out of a RG630 substrate (Coronado, BelOptik, Lunt - but NOT the Baader DERF), you could also use the BelOptik UV/IR cut filter on KG3 as a ITF replacemnt. If you use a Baader DERF, then you would have to use the Maier or BelOptick ITF relpacement filters which do incorporate an RG630 as a filter element.


  • TerryWood likes this

#7 TerryWood

TerryWood

    Soyuz

  • *****
  • topic starter
  • Posts: 3,545
  • Joined: 15 Mar 2012
  • Loc: USA

Posted 20 November 2017 - 12:07 PM

Bob, Thanks for the in-depth explanation regarding these filters! I think I would like to retain the current ERF for now and go with the easiest ITF replacement with IR-cut. If I'm understanding you correctly, the KG3 filter is also part of the BelOptik ITF? Or is the KG3 filter an additional filter screwed into the nosepiece? I just want to make sure I have my ducks in a row. Thanks again! V/R Terry

#8 BYoesle

BYoesle

    Fly Me to the Moon

  • *****
  • Posts: 6,829
  • Joined: 12 Jun 2004
  • Loc: Washington USA

Posted 20 November 2017 - 01:34 PM

Hi Terry,

 

The BelOptik ITF REPLACMENT filter does not include an ITF LAYER to block near and long-wave IR, it uses an IR blocking hard coating added to an RG630 filter for UV and near IR blocking, and a KG3 heat absorbing filter (AR coated) to block long wave IR. So you have all the benefits of an ITF (induced transmission filer, for near and long IR blocking), WITHOUT the worry of the ITF's silver layer deterioration. It appears to be a direct drop-in replacement as well:

 

http://beloptik.de/e...or-coronado-bf/

 

If you have an "upstream" RG630 filter (ERF, etc.) then you could realize an improvement in image brightness by using the simpler (and cheaper) UV/IR cut on KG3, which is nearly identical but eliminates the RG630 substrate. If you want it to be a direct drop-in replacement, Oliver can do that for a minimal additional charge - tell him Bob from Washington State sent you ;-)

 

http://beloptik.de/e...locking-filter/


Edited by BYoesle, 20 November 2017 - 01:50 PM.

  • Lost in Space and TerryWood like this

#9 TerryWood

TerryWood

    Soyuz

  • *****
  • topic starter
  • Posts: 3,545
  • Joined: 15 Mar 2012
  • Loc: USA

Posted 20 November 2017 - 02:04 PM

Bob, Thanks for the crash course on filters! I'll digest all of this and when I get ready to replace the ITF I'll contact BelOptik. I'll be sure to tell them you sent me! V/R Terry

#10 ASTROTRUCK

ASTROTRUCK

    Viking 1

  • -----
  • Posts: 604
  • Joined: 02 Jan 2010

Posted 27 November 2017 - 12:51 PM

 apparently then if we have the meade coronado HA etelons with their ERF's  along  with their bf - if one does not wish to replace the erfs also - the only filter to use as replacement in the bf's  is the beloptic as it incorporates the iruv also.

meire filter  needs that additional iruv  placed in front of the bf reducing contrast.

 

am i correct people about the beloptic ?



#11 BobPeck

BobPeck

    Lift Off

  • -----
  • Posts: 2
  • Joined: 12 Jan 2009
  • Loc: California

Posted 28 November 2017 - 09:47 PM

Does anyone know the diameter of the ERF in the pre meade solarmax 90?

Is there a brand mentioned above that makes a direct drop in with a RG630 substrate that would fit the solarmax90?

Thanks for your response

Bob Peck



#12 GUS.K

GUS.K

    Viking 1

  • -----
  • Posts: 742
  • Joined: 13 Aug 2014
  • Loc: Katoomba, NSW, Australia.

Posted 29 November 2017 - 01:06 AM

Here's a shot of the three ITF filters, top row shows the side which faces incoming light, bottom row is side facing eyepiece.IMG_2546.JPG


  • Lost in Space, Greg77, TerryWood and 1 other like this

#13 ASTROTRUCK

ASTROTRUCK

    Viking 1

  • -----
  • Posts: 604
  • Joined: 02 Jan 2010

Posted 08 September 2019 - 05:27 PM

per above - - apparently then if we have the meade coronado HA etelons with their ERF's  along  with their bf - if one does not wish to replace the erfs also - the only filter to use as replacement in the bf's  is the beloptic as it incorporates the iruv also.

meire filter  needs that additional iruv  placed in front of the bf reducing contrast.

am i correct people about the beloptic ?

 

why even buy a meier filter if i need to add a iruv filter in front anyways ??



#14 Bagwell

Bagwell

    Vostok 1

  • *****
  • Posts: 195
  • Joined: 05 Nov 2018
  • Loc: Houston, Texas

Posted 16 August 2020 - 01:30 PM

about a year old thread, but  thought I would post here since I recently bought a Solarmax II 60 with a BF10 and seems like the ITF is failing along with the silver surface on the diagonal mirror.  I will post pictures later.  

Wanted to be sure about the filter replacements listed above.  It seems that either the Bel Optic drop in replacement or the Maire drop in replacement are both fine without adding an ir/uv cut or any other filter in on the objective side of the ITF correct?  It is interesting that the Bel Optic version has a yellowish objective end surface rather than the other two (original coronado and maire) .  The difference is what made me ask to clarify the answer that either replacement ITF filter need an additional filter added to work and be safe.    I would also love to find a double stack for this scope sometime, but currently Meade Coronado doesnt seem to be producing them and discontinued them until the III versions come out.  

 

Thanks, 
Vaughn



#15 vincentv

vincentv

    Mariner 2

  • *****
  • Posts: 208
  • Joined: 16 Apr 2017
  • Loc: Costa Rica

Posted 16 August 2020 - 09:40 PM

Neither the beloptik nor maier replacements *need* another filter. Both safely replace the stock ITF.

Since the maier is of the same type as the original ITF many speculate that a UV/IR cut filter will prolong its life. Either the way the anecdotal evidence in forums says the maier lasts longer than the coronado ITF. Installing it yourself in 10min instead of dealing with coronado is icing on the cake.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics