Which White Light Wedge?

[David Smith]

Time to replace my aging and slightly battered white light wedge, the question is what to go for? It will be used primarily with my 120mm achro Evostar scope but I am torn between Lacerta and Lunt options.

My current 1.25" Lunt  copes with the 120mm objective with no issue (gets a little warm but not so hot as to be dangerous) so I am thinking 1.25" again as most of my eyepieces I use for solar are that size. Also back focus is a consideration, based on some measurements I think I may struggle with the Lacerta 2" model getting to focus, especially for imaging with a DSLR.

The Lunt is a proven performer but there are some very positive reviews of the Lacerta on here so I inclined to think I will go down that route.....

Thoughts, other options, consideration? All contributions welcomed

Cheers, David

 

[xtreemchaos]

i have to say Lunt because i havnt try anything else "thats not a lot of use is it", ive been looking at sol thismorrning David and the seeing is terrible, not a lot to see 2 bright patches with one tiny spot, couldnt make out the small proms with the darn seeing. hope you have better. charl.

[David Smith]

Thanks Charl. The Lunt seems the "safe" option, just wandering if there is a "better" option. I managed a quick look this morning between the clouds, agree on the seeing plus it's blowing a gale here! My low profile EOS T-ring arrived whilst I was away this week and the good news is I can now reach focus with my dslr on the white light wedge If it were not for the broken retainer screw on my wedge then I would not be looking to replace it but I am not happy with my DSLR balanced atop the wedge without any kind of restraint

[xtreemchaos]

thanks David, carnt you redrill and tap another thread for the retainer screw ?. charl.

 

[David Smith]

Someone who knows how to do these things probably could

[xtreemchaos]

all you need is a cheap tap n dye set about a tenna and a drill bit and the use of a vice, or take it to a engineering shop/ garage/ blacksmiths and let them do it it should cost no morethan £10 and then it would be like new. charl.

[David Smith]

Off to youtube to have a look and maybe learn something.....

[xtreemchaos]

yer theres loads of vids on there, if i still had a decent tap n dye set id sort it for you but alas i lent mine out a few years ago and it hasnt found its way back yet ?

[Pete Presland]

I have  been using my Lunt for years with no problems, so that's the one for me as well.

Regarding the threaded hole, is it the screw that holds the eyepiece/nosepiece in position? If so that's a 4mm thread I think.

Which you could drill out to 4.2mm diameter then tap to 5mm. I use 5mm thumb screws at work and would be more than happy to post you a couple and also lend you a drill and 5mm tap + wrench if you want to give it a go.

[AdeKing]

On 09/03/2019 at 11:04, David Smith said:

The Lunt is a proven performer but there are some very positive reviews of the Lacerta on here so I inclined to think I will go down that route.....

I have the 1.25" Lunt and the 2" Lacerta and for 99% of the time I reach for the Lunt. 

The 2" Lacerta is a very solid lump of metal and makes balancing my short Fracs a challenge. I've used the Lunt on apertures up to 100mm with no issues and have seen reports of people using it on up to 150mm diameter. 

Bear in mind that the 1.25" Lacerta requires you to remember to attach the ND filter to the eyepiece thread whereas on the Lunt and 2" Lacerta the filter is permanently attached inside the wedge so can't be removed without requiring some effort. 

The Lacerta does allow you to dim the image more using a single polariser and rotating the eyepiece than the Lunt does because the Lacerta wedge is cut at the Brewster angle but that is not something that I miss on the Lunt. 

If you're not using 2" eyepieces and are not using a massive Frac then I'd go the Lunt route. 

Ade

[AdeKing]

On 09/03/2019 at 11:37, David Smith said:

If it were not for the broken retainer screw on my wedge then I would not be looking to replace it but I am not happy with my DSLR balanced atop the wedge without any kind of restraint 

If the screw has broken off in the hole then a local engineering / metal worker should be able to get it out for you. 

I managed to get one out of one of my mirror diagonals by applying pressure to the broken end with a dried out Sharpie pen an then turning slowly and firmly clockwise. Eventually there was enough thread protruding inside to work it out with my fingers. 

Just remember to work the brass ring round the groove so that you can see the threaded hole from inside the eyepiece barrel on the wedge. 

[Rusted]

My Lacerta 2" has not suffered above a nicely hand warm 85F even when tracking the sun for literally hours all day on my 180mm f12, iStar refractor.
It has the 2" ND filter fitted permanently inside. I added a 2" polarizing on a rotating top fixture plus a 2" UV/IR block underneath.
A 1.25" Baader Solar Continuum sits in the eyepiece. I pushed it up to 220x yesterday.
Just trying to make something of the tiny sunspot. It was hardly any larger and certainly no softer.
Which speaks volumes of the quality of the Lacerta prism and iStar objective.
I would need to shorten my OTA to use my binoviewers but wouldn't even try to hang it off a small refractor.
Simply because of serious balance issues. I just slide my several, sliding, OTA balance weights along.

EDIT: The correct way to remove a broken screw is to drill it centrally and then use a reverse LH thread screw extractor.
I regularly drill and tap my EP holders to have two or even three radial screws to aid centring and grip.
It requires considerable care, practice and patience not to make a loose thread for the new screw[s.]
Which is useless.