April 2015

Financials:

Opening balance March 1 $1784.67

Dues—new members $60.00

Dues—renewing members $30.00

Revenue for subscription for member to Astronomy Technology Today $140.00

Payment to charitable organization registration with Secretary of State $15.00

Subscription for member to Astronomy Technology Today $14.00

Ending balance March 31 $1859.67

Current membership in BAS: 33 members

18 attended this month’s meeting

Virgil’s astronomy news:

Showed picture of category 4 typhoon

April 4 lunar eclipse—total (if not for haze cover)—about half of group watched

Spots have been seen on Ceres; Dawn can’t take pictures right now. Ceres is 2% of mass of moon but 1/3 of its weight. Dawn orbited Vesta. Dawn is the first craft that has orbited 2 objects.

New Horizons is closer now to Pluto than we are to the Sun. Closest approach will be on July 14 and has been plotted down to the second.

Ganymede is the largest moon in the solar system, 10 times the mass of Pluto. It has auroras and inferred oceans.

Mars:

Rover’s view from Mars March 18—2-tone mineral veins. Think these had to have been formed by water over many wet and dry phases.

Have found nitrogen on Mars. Mars is the only planet inhabited solely by robots!

Milky Way: may be 30 percent bigger than we thought it was. Nine new dwarf galaxies have been found in our vicinity near the Magellanic cloud.

Would anyone be interested in solar glasses for eclipses?

Astrophotography 101, Part 2 by Rick Bryant

Rick has been a member of the BAS for 18 years and has 15 years’ experience in astrophotography to share.

His plan for skills to develop for beginners:

February meeting—introduction by Bob Young

April—skills development

June—intro to image processing

Barn Door mounts

Workshop for absolute beginners

More advanced workshop

3 sets of skills needed:

• Learn the night sky

• Learn how to use YOUR equipment in the dark

• Learn YOUR software

Your interests in photography:

Start with what you have

Keep good records

Develop your skills

Determine your interests

Critically evaluate your needs before you spend money

Lessons learned # 1 : Be prepared

Check equipment before you take it to the field

Get the latest information on special astronomical events you want to photograph

Make an equipment checklist

Plan each astrophotograph in advance

Use star wheels and charts

Put charts in a notebook with acetate sheets

Lessons learned # 2:

A universal image does not exist yet!

Lessons learned # 3:

Tracking tolerance

Usually 5-10-15 minutes of exposures

Basic rules of thumb:

600 rule—wide field “good” images

250 rule—high resolution/magnification

Convert lens to full frame size (25 mm)

600/38 = 16 seconds

He uses 350/400.

Lessons learned # 4:

Polar alignment tolerance (see chart from his presentation)

Lesson # 5:

It is easy to over-expose

Lesson # 6:

(Auto)focus

Learn how to manually focus at infinity

Must learn *consistent* manual focus

SLR can focus past infinity

Electronic focus—focus indicator; daylight testing and verification. Verify infinity in full prior to use.

Autofocus is limited to sun, moon, etc.

He marks lens to where infinity focus is.

Lesson # 7: Batteries

They die quickly due to cold, long exposure time and constant drain.

Have extras, fully charged, and keep them warm.

Be prepared to use battery substitutes—AC and/or DC.

(Note: Autoguiding—tracking just that object you want to photograph—is not a part of beginning astrophotography.

Example: photo of crescent moon at 33,000 feet)

Learn how to—

Focus using zoom

How to change batteries and charge your equipment

Use shutter speed

(He showed a picture of Mercury, crescent moon, Venus and Saturn taken with a level 1 camera, remote release, and tripod.)

You can use a fence post or hood of car to balance camera on.

Lots of newer cameras have remote releases

Step it up a notch: Image Processing

He showed a “Level 2” picture of comet Panstaars taken March 13, 2013

First tool to learn how to use: Histogram

With this, use mid-tone stretch; use mid-tone slider. Clip shadows/highlights to bring out more (for example) of the tail in a comet. Black out trees.

Take it up another notch: Stacking pictures

You want to separate the signals from the noise. You want to even out the noise and average it out, then stretch the image to get more detail.

Stack pictures in 10 second time frame 1.3 seconds apart; 6 ½ seconds over a 10 second period

Not all image processing software will let you stack layers.

He showed a “level 2” picture of the Grand Canyon by moonlight. Used a tripod, stacking, basic processing, photo merge. He took slices and stitched them together. Software he uses finds the fit; Photoshop can help you find the fit.

Step it up a notch:

Simple tracking mounts

Longer exposures; manual or motorized

A simple barn-door tracker costs $20.00, but you can get others costing $80.00 or more, shipped.

He showed a “level 3” picture of comet Neat taken with a camera, remote and manual tracking with a 60-second exposure, taken May 15, 2004.

Start tracking, then take picture. This is a skill to learn; you can master it in one night.

He showed a “level 3” picture of Southern Orion, taken with a camera, remote, manual tracker, stacking and processing. Orion is very photogenic!

If you take 20-40 exposures, you get more detail.

You can get free image stacking software; Deep Sky Stacker is one of the best

His philosophy in astrophotography is to remove as much human made noise as you can.

Dark frames (cover lens cap)

Flat frames (use white or light gray card)

Bias frames (fastest shutter speed that you can do)

Learn the scientific side of image processing; learn about light pollution gradients

He showed a “level 3” picture of Comet Lovejoy taken Jan 16, 2015 with camera, remote, motorized tracking and stacking and processing

He showed a “level 3” picture of Orion taken with camera, remote, motorized tracking, stacking and processing

He showed a “level 3” picture of the Milky Way, Cassiopeia to Orion, taken with camera, remote, motorized tracking, stacking, processing and photo merging, covering 100 degrees of the night sky.

Take it up a notch:

Photograph through a telescope. Higher power/shorter exposure time.

Future seminars:

Barn door mounts

Intro to image processing in June

Intro to Pixinsight LE

Intro to Deep Sky Stacker