Filter Help

Hmmm. If you are doing eyepiece projection, then the filter screws into the eyepiece/Barlow and the camera images through the eyepiece/Barlow . So that should mean your image is suitably passing though the filter.

If you are attaching the camera directly to the OTA then I'm not sure of the solution. I'm sure there is one - but I don't really know that much about the way (D)SLR's attach to OTA's other than there are lots of options. I'm sure you could lash in a filter somewhere between the camera and OTA provide you have the right threaded bits. It migh mean going for a two inch filter (to avoid vignetting and coverage issues) thus increasing the cost on what is already (probably) quite an expensive item.

I'm sure other here can jump in and offer you more detailed advice or ask you more of the right questions.

Dave

To attach original Nikon D-series DSLRs at prime focus you need a suitable extension tube with a T-thread at the camera end and a Nikon F-mount T-adaptor. The extender is needed to provide full coverage of the DX chip. A longer extension tube would be required to provide the same coverage on Nikon's new FX chip (similar in size to a 35mm film frame) but that's only in the flagship D300 that was recently announced. I use a D50 this way with a 40mm extension tube.

Many focusers and diagonals are not capable of supporting a DSLR attached to an eyepiece for eyepiece projection because the assembly is too heavy. For that I originally used a Coolpix 4300 compact with a UR-E4 adaptor ring and a Scopetronix Maxview eyepiece (available in 14mm and 18mm with a 28mm thread). I now use a Coolpix P5000 with a UR-E20 adaptor ring and the same eyepieces and I plan to get an adaptor that will fit my Hyperion eyepieces.

2" Newtonian focusers and 2" diagonals clamped into heavy duty focusers with brass compression rings or attached to an SCT thread might support the weight of a DSLR for eyepiece projection, but I wouldn't recommend it because the weight is amplified by the length of the adaptor assembly.

Hi guys,

Sorry to pester ye with questions but is there such a thing as an all round filter i.e. can make nebula, light pollution and planetery and lunar appear clearer or have better quality.

Probably a stupid quetion to ye guys.

Thanks

No, there is no such filter.
filters are task specific, you can get a green one for dimming the moon and an O3 or Hb for nebula, and coloured filters for enhancing planetary features.

There is also no such thing as a stupid question.

Ok Thanks Dave What colours would you recommendfor Mars, Jupiter, Saturn, Venus and the Moon :

John, in regard to the camera being to heavy could i put a tripod under the camera.
thanks for the helpful advice.

Hi guys

Have another question for ye, when i look for filters on any website it says (something)% transmission.

What does that mean?

A good question John,
If a filter has say 98% transmission at a frequency it means that the filter is very transparent at that frequency and if the filter has 0% transmission at certain frequencies then it is opaque at those frequencies, light pollution filters have 0% (or near it) transmission at sodium light frequencies.

Thanks Dave
Helpful advise.