RDF For Bresser Messier 90/900

[JohnC260]

Hi All,

I’m really struggling with the stock finder scope that came with this, an RDF was recommended to me but there are loads out there. 

Please could someone steer me in the right direction. 

Thanks

John

[emadmoussa]

https://www.ebay.co.uk/itm/Opticstar-Red-Green-Dot-Finder-RDF-UK/323031693373?hash=item4b3630783d:g:k44AAOSwvktaazTe:rk:1:pf:0

 

[Rob]

I think you have the twin screw base finder. You may need to either fit a new vixen style finder base, or buy a RDF that has the same base to retro fit.

https://www.365astronomy.com/Celestron-Finderscope-Star-Pointer.html

and the base swap to change to the vixen style (see emad's MRF above) is https://www.firstlightoptics.com/finders/baader-universal-quick-release-finder-base.html

Rob

[JohnC260]

It does have the twin screw base.

I was looking at the Baader Sky Surfer III as I was hoping one of the many fitting options would work.

Is the base you listed needed for both the Celesteon you listed and Emads one Rob?

[Rob]

From what I recall the Celestron RDF comes with multi bases (worth a check) which would include the Vixen type that would work with the Baader Vixen finder shoe. However, if you are looking to purchase the Baader base it will open up to many types of finder for you.

That all said the Baader Sky surfer III does offer multi bases, plus the base you need at £29!. So a cheaper route all round to be fair

https://www.harrisontelescopes.co.uk/acatalog/baader-skysurfer-iii-finder.html?gclid=EAIaIQobChMItquou-nl3wIVLrHtCh2cXAG-EAQYASABEgKXNvD_BwE

[Rob]

This might interest you also John!.

 

[JohnC260]

that article is actually really helpful, someone with a 102 Bresser commented that they couldn't align it with their scope, mines smaller but possibly could have same issues.

I will have a look at the Celestron and Emads options again.

Emads is really tempting as it's all metal..

[Rob]

Always well worth the home work before you buy. Good.

 

[Ricochet]

A rigel quickfinder would probably be a good choice. It has self adhesive bases and could be put further up the OTA which may be easier to use. 

[JohnC260]

I think Emads with the Baader base, I really liked the Celestron though especially at that price, but I like the fact it's a metal build.

I had looked at the Baader Sky Surfer V, but it's not cheap, it does come with the base I require though.

[Rob]

Yes the Baader V is nice. All metal & comes with the base/shoe included

https://www.tringastro.co.uk/baader-40mm-skysurfer-v-red-dot-finder-1430-p.asp?gclid=EAIaIQobChMIhdGclvbl3wIVwrTtCh1-lAFlEAkYASABEgKSfPD_BwE

[JohnC260]

That’s the best price by far, would it be crazy spending that for a £120 Bresser scope?

I don’t mind spending for good items and I suppose I can fit it to potential future scopes. 

[Ricochet]

2 hours ago, JohnC260 said:

That’s the best price by far, would it be crazy spending that for a £120 Bresser scope?

I don’t mind spending for good items and I suppose I can fit it to potential future scopes. 

It depends how much you like the scope.

[Louis D]

8 hours ago, JohnC260 said:

That’s the best price by far, would it be crazy spending that for a £120 Bresser scope?

I don’t mind spending for good items and I suppose I can fit it to potential future scopes. 

I like the Rigel QuikFinder despite it being all plastic, including the base.  It has a 1/2 degree and a 2 degree circle for aiding in star hopping, a very good dimming circuit, and a variable speed pulser, all built in.  It also weighs next to nothing, so it doesn't upset balance at all.  I'm still using the original lithium button cell 18 years after I bought it, so it has very good battery life.  It only costs £34 from FLO and comes with two bases that can be attached with the supplied double-sided foam tape or be screwed in place.  I've knocked it on doorways carrying my assembled scope outdoors and never had it break, so it's pretty durable.  The only downside is that it shows a bit of parallax on the sky, so you must keep your eye centered behind it for best pointing accuracy.

[JohnC260]

Hmmm this could prove annoying. 

I removed the thumbscrews for the finder mount, and they don’t screw into the tube, these are sticking out, if I loosen the bolts they become loose. 

Not sure how well the Baader dove tail mount would fit to this. 

[Ricochet]

45 minutes ago, JohnC260 said:

Hmmm this could prove annoying. 

I removed the thumbscrews for the finder mount, and they don’t screw into the tube, these are sticking out, if I loosen the bolts they become loose. 

Not sure how well the Baader dove tail mount would fit to this. 

Do the bolts match the holes on the finder shoe? (Or is it just one hole on the Baader?) If so you would have to remove the focuser, so you can get your hand inside the tube, remove the existing bolts, and then fit the shoe with the correct length bolts. 

[JohnC260]

The Baader from what I can see has three holes, two are recessed groves, the third a central counter sunk hole. 

The thought of removing the focuser terrifies me lol

[JohnC260]

My other thought, I would need to do some measurements, if those screws are far enough apart, I could still use the Baader shoe if the thumb srcews don't interfer with the dove tail.

I could use a lock washer beneath them as the Baader shoe is quite wide.