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Coronado Maxscope 40 Hα Solar Telescope

I ordered a Coronado PST at AstroFest in February 2004 to watch the Transit of Venus on June 8th 2004 through H-alpha.

 However, when May had arrived with no sign of any PSTs being shipped, I changed my order to the Maxscope40 which was available for immediate delivery.

I have MaxScope40 with Hα and BF10 filters, T-Max filter Detuner  and CeMax eyepieces.

Initial views were good and prominences were immediately visible - my other telescopes had white light filters so sunspots I had seen before but the prominences are something to behold. Like seeing Saturn's rings and Jupiter's moons for the first time!

But where is the manual and instructions for the instrument? The sole enclosure was a miniature instruction sheet (A one-third silver of a standard A4/legal sheet of paper). I had to get out the August 2002 Sky & Telescope, page 52 to understand operation and setup. The least Coronado should do is to enclose a reprint of the S&T test report.

Many people have sat entranced by the features that this telescope reveals on the Sun. The features are ever changing: prominences come, change shape and go, sometimes within 15 minutes. The surface details are many and varied and produce much discussion as to their source, formation and structure. The interest shown by those who have never viewed through a telescope before is far greater Ha with  than when using white light sun filters with other telescopes. Certainly this scope is a good investment if you can afford it. I hope to see through a Coronado PST sometime!

Alignment to Sun (method 1)

The Maxscope40 arrives with no built-in method of easy alignment to the Sun.

I have solved this problem by sticking three small squares of white paper onto the top edges of the lower supporting ring as shown highlighted by the red rings in the left hand picture. 

I mount the OTA as centrally as I can within each ring by trying to make the lengths of screw showing of equal length.

I then align the telescope so that there are no bright sunlight areas on the three pieces of paper, i.e. the two rings are aligned to the sun. The picture on the right shows unaligned position when one piece of paper is only half in shadow.

The telescope should then be well aligned to the Sun. I have found that, when set up in this manner, the Sun is always visible through a 24mm eyepiece.

When a tin of white paint is to hand I shall remove the paper and add three small squares of paint.

Alignment to Sun (method 2)

Further thoughts on how to make aligning the telescope easier led me to make a Model 2 alignment tool.

This works to the regular pattern of projecting a small hole in the front plate onto a rear panel which has a ring target - adjusting the telescope to bring the dot image of the sun into the centre of the target aligns the telescope to the Sun.
 

The tool is made from a short length of plastic water pipe just over 1.25" diameter. I cut the pipe square and inserted and glued black paper inside the tube to reduce reflections. The outside of the tube was also covered in black paper - solely because I thought it looked better!

The objective end of the alignment tool is the top from a 35mm Fuji clear film holder which happens to be a tight fit to the inside of the tube. I glued a circle of black paper to the inside of this top and drilled a 1/8" hole in the centre.

The sighting end of the tube was covered with a circle cut from a kitchen storage tray.

The assembly was then mounted onto the rings holding the OTA using elastic bands aligned so that the tube was pushed against the mounting screws and thus was in a fixed position.

The final task was to align the telescope to the Sun using my previous method Then, when aligned, to quickly draw a small target circle around the position of the bright image of the Sun on the translucent screen.
 

Slow Motion Tripod Mount

[Item Image]Initially I mounted the MaxScope40 directly onto a video camera tripod (see picture at top of this page).

This mount did not give a fine, steady movement - the telescope is quite heavy with eyepieces not to mention digital camera or webcams. I searched around and bought an Orion Precision Slow Motion Adaptor from SCS Astro of Taunton in UK at £27.00 incl. VAT.

The Coronado telescope mounting bracket which supports the OTA rings is tapped for the standard camera tripod thread.

The telescope is now far easier to use and the slow motion adjustment fine for following the Sun.



Sun Shield

I found that I had to wear a wide-brimmed hat to use the scope - firstly to shade my head and, more importantly, to shade the eyepiece from the bright sunlight.

There are several accessory companies producing shields but I found a baking tray in the cooking section of Tesco, our local supermarket, and cut an aperture to match the diameter of the Maxscope and had the shield within an hour.

I was lucky to find a baking tray that already had a large lip already folded - I cut a 1/2" guide slot and secured the lip between the Maxscope mounting and the tripod.

A small square aperture cut just above the OTA allows light for the alignment tool through the sun shield.

PiggyBack Mount on LX200 GPS 10"

Coronado Maxscope 40 Hα telescope piggy-back mounted on Meade LX200 GPS 10" SCT.

The sun moves so quickly across the field of view of the Maxscope 40 mounted on a photographic mount that, when using webcam for photographing the sun, I need to mount the solar telescope on a piggy-back mount on my LX200 GPS 10" SCT.

Note Maxscope 40 has Philips ToUcam inserted for webcam capture.

I use my normal routine for pointing the LX200, with its white light solar filter, towards the sun (drive and slew the telescope with SkyMap Pro 10 on laptop computer) and then fine adjust the Maxscope 40 to point at the sun using the slow motion adaptor and my solar alignment tube as above.

When using the Philips ToUcam, I find that setting the camera to an exposure of 1/30 second with only a little gain provides a good starting situation.

I also add some balance weights to the front of the telescope to balance the load of the Maxscope at the rear of the LX200. 



Shoot the Sun with two barrels!

 

Coronado (now part of Meade) brought out a version of their PST using the CaK frequency. I decided this needed to be mounted on a single plate with both the CaK PST and my Maxscope Hydrogen-alpha locked together enabling quick comparison views of the sun through the two frequencies. I could not find a standard astronomical store supplying such a plate; I was pointed to a specialist supplier, Ambermile, who previously were known for manufacture of Artemis camera kits but are now broadening their range into wider astro engineering. The plate is clearly seen in the above images and works well; I can recommend their pleasant and efficient service. Link to Ambermile.

For more details of the CaK PST click the image -> 

For observations I have made with the MaxScope 40 click the image ->

For observations I have made with the Coronado CaK PST click ->       

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