Merlin66

Definitely NOT the way to go! Optics and grease don't play well together.

When testing the Meade SCT (10" and 12") I mounted the artificial star (Hubble torch) on a photographic tripod and used the full length of the garden. You don't need complete darkness to test.

Just a question... We normally take flats to correct for dust bunnies, vignetting etc. If we use an LED panel then the light is anything but constant across the spectrum, also when using a light source the spectral distribution will follow the temperature Planck curve and have higher intensity towards the red/IR. What impact would/ does such a skewed intensity curve have on the images being produced???

The SimSpec spreadsheet can be used to calculate the (probable) performance of the LowSpec spectrograph with various gratings/slit gaps/camera. SimSpec V4.3_Paul3D.xls SimSpecV4.pdf

I use the ATiK 314L regularly (Win7) for spectroscopy on the C11. AstroArt for acquisition and I use the ASCOM driver. A good power cable and USB is mandatory.

Just a comment: The secondary mirrors we buy are not elliptical! They are a cylindrical section ( easier to make)

I use the Ronchi for testing... Using a artificial star indoors - find the longest space you can, suggest at least x10 the focal length..... longer is better.

Yeah, we have similar here is Oz. I use it to cover my HEQ5 Pro mount. works well.

Or Vegemite lids...

Ahhhh, sorry. I should have read the thread from the beginning.

I agree. The first test only shows that the focuser is aligned with the centre of the objective. Once this has been established, I believe any off centre pointer plate laser dot, points to the fact that the objective is not collimated to the focuser. If the objective is not collimatable, then there's not much you can do about it.

I had the same issue fitting a Baader Cool 2” wedge to the Genesis OTA. The clip lock feature added to the back focus needs. I had to remove the clip lock and use a SCT adaptor to get focus.

Not sure about the “spring” reference. I haven’t seen one on an NEQ6PRO mount.

Regards, getting up early in the morning to observe. I once asked Bill Bradfield how he managed to get up early to do his comet searching..... He said he used the “Indian alarm clock” ????????? I smiled as he explained: I fill my bladder before going to bed....it means I have to get up....ideal for getting up early for comet seeking.

Start with the conventional focuser to objective alignment test with the laser, #1 in your list. Any mis-collimation of the objective to the OTA and focuser will show in the pointer plate as a mis-collimated point. You need to collimated the focuser first, then look at the objective.

Gareth, The sweet spot for solar seems to by around 100 to 120mm aperture, based on local seeing. The ETX125 would be a good compromise.

Garett, The ETX 125 fitted with a Baader Solar Screen would be an ideal white light solar observing/ imaging system. Seeing conditions don’t always allow much benefit for larger apertures.

What about these? https://www.youtube.com/watch?v=Ci_aMmO4DBA https://www.youtube.com/watch?v=xuvUew-0ccs

Yeah, The usual laser alignment test, just checks the alignment of the focuser to the centre of the objective..... it’s that extra step of using the reflection from the objective to verify the collimation of the objective to the OTA/ focuser that’s the different and interesting point.

I'm in the process of re-building a Spectroheliograph and a PST mod. In the SHG I have, what I think is a good lens, a Carton 100/1300 objective. I normal collimate the OTA - focuser to objective, using a objective target and a laser pointer, followed by the Cheshire side illuminated to show the "doughnut" reflections a la Suiter (p121-123) I now have a very good variable brightness collimator available, and carried out the usual focuser to objective test.....BUT I noticed a reflected "dot" in the collimator target...this seems to be reflected from the optical surface(s) of the objective. This reflection can then be used to collimate the objective lens to the OTA and focuser. This is something new to me, having never used a collimator for this test. I haven't seen it mentioned as a way of collimating the objective, so I thought it would be of interest.

In the previous diagram.... Part B screws into Part C, and compresses an internal O ring onto the motor shaft, then Screw A "locks" it in place. I think this is designed to give a "flexible joint" between the motor shaft and the focuser spindle. All the kits I have, contained both the silver and black flexible connectors, as mentioned above.

The one's I use today came from Small Parts in Australia. https://www.smallparts.com.au/store/categories/timing+belt+lengths+categories/ While in the UK I got them from MotionCo https://www.motionco.co.uk/timing-belts-timing-belts-c-25_38_27.html I use the 6mm bore 30 tooth pulley and length of XML belt to suit, usually 100 XML.

The longer screws supplied with the SW focus motor are M3 x 12. HTH

I use a piece of software which shows the position of the Sun throughout the year. https://www.suncalc.org/#/-38.1667,144.7167,3/2020.06.21/12:35/1/0 This can be used to align the mount at local noon, then mark the position of the tripod feet for the next time. Works for me

Undoing the retaining ring, shown in the first illustration above, is the easier way of changing the ITF filter. Just watch when re-fitting, it has a slight tilt....